diff --git a/docs/datastructure/linklist.md b/docs/datastructure/linklist.md
index d709c71..536b0d0 100644
--- a/docs/datastructure/linklist.md
+++ b/docs/datastructure/linklist.md
@@ -24,11 +24,8 @@ import (
 
 ### 1. SinglyLink
 
-
-
 - [NewSinglyLink](#NewSinglyLink)
 - [Values](#SinglyLink_Values)
-
 - [InsertAt](#SinglyLink_InsertAt)
 - [InsertAtHead](#SinglyLink_InsertAtHead)
 - [InsertAtTail](#SinglyLink_InsertAtTail)
@@ -39,12 +36,26 @@ import (
 - [Reverse](#SinglyLink_Reverse)
 - [GetMiddleNode](#SinglyLink_GetMiddleNode)
 - [Size](#SinglyLink_Size)
-  
 - [IsEmpty](#SinglyLink_IsEmpty)
 - [Clear](#SinglyLink_Clear)
 - [Print](#SinglyLink_Print)
 
+### 2. DoublyLink
 
+- [NewDoublyLink](#NewDoublyLink)
+- [Values](#DoublyLink_Values)
+- [InsertAt](#DoublyLink_InsertAt)
+- [InsertAtHead](#DoublyLink_InsertAtHead)
+- [InsertAtTail](#DoublyLink_InsertAtTail)
+- [DeleteAt](#DoublyLink_DeleteAt)
+- [DeleteAtHead](#DoublyLink_DeleteAtHead)
+- [DeleteAtTail](#DoublyLink_DeleteAtTail)
+- [Reverse](#DoublyLink_Reverse)
+- [GetMiddleNode](#DoublyLink_GetMiddleNode)
+- [Size](#DoublyLink_Size)
+- [IsEmpty](#DoublyLink_IsEmpty)
+- [Clear](#DoublyLink_Clear)
+- [Print](#DoublyLink_Print)
 
 
 <div STYLE="page-break-after: always;"></div>
@@ -542,4 +553,467 @@ func main() {
     
     lk.Print() //[ &{Value:1 Pre:<nil> Next:0xc0000a4048}, &{Value:2 Pre:<nil> Next:0xc0000a4060}, &{Value:3 Pre:<nil> Next:<nil>} ]
 }
+```
+
+
+
+### 2. DoublyLink
+DoublyLink is a linked list, whose node has a value, a next pointer points to next node and pre pointer points to previous node of the link.
+
+### <span id="NewDoublyLink">NewDoublyLink</span>
+<p>Return a doubly link instance</p>
+
+<b>Signature:</b>
+
+```go
+type LinkNode[T any] struct {
+	Value T
+    Pre   *LinkNode[T]
+	Next  *LinkNode[T]
+}
+type DoublyLink[T any] struct {
+	Head   *datastructure.LinkNode[T]
+	length int
+}
+func NewDoublyLink[T any]() *DoublyLink[T]
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    link "github.com/duke-git/lancet/v2/datastructure/link"
+)
+
+func main() {
+    lk := link.NewDoublyLink[int]()
+    fmt.Println(lk)
+}
+```
+
+
+
+### <span id="DoublyLink_Values">Values</span>
+<p>Return a slice of all node value in doubly linklist</p>
+
+<b>Signature:</b>
+
+```go
+func (link *DoublyLink[T]) Values() []T
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    link "github.com/duke-git/lancet/v2/datastructure/link"
+)
+
+func main() {
+    lk := link.NewDoublyLink[int]()
+
+    lk.InsertAtTail(1)
+    lk.InsertAtTail(2)
+    lk.InsertAtTail(3)
+
+    fmt.Println(lk.Values()) //[]int{1, 2, 3}
+}
+```
+
+
+
+
+### <span id="DoublyLink_InsertAt">InsertAt</span>
+<p>Insert value into doubly linklist at index, index shoud be great or equal 0 and less or equal number of link nodes</p>
+
+<b>Signature:</b>
+
+```go
+func (link *DoublyLink[T]) InsertAt(index int, value T) error
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    link "github.com/duke-git/lancet/v2/datastructure/link"
+)
+
+func main() {
+    lk := link.NewDoublyLink[int]()
+
+    lk.InsertAt(0, 1)
+    lk.InsertAt(1, 2)
+    lk.InsertAt(2, 3)
+    lk.InsertAt(2, 4)
+
+    fmt.Println(lk.Values()) //[]int{1, 2, 4, 3}
+}
+```
+
+
+
+
+### <span id="DoublyLink_InsertAtHead">InsertAtHead</span>
+<p>Insert value into doubly linklist at head(first) index</p>
+
+<b>Signature:</b>
+
+```go
+func (link *DoublyLink[T]) InsertAtHead(value T)
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    link "github.com/duke-git/lancet/v2/datastructure/link"
+)
+
+func main() {
+    lk := link.NewDoublyLink[int]()
+
+    lk.InsertAtHead(1)
+    lk.InsertAtHead(2)
+    lk.InsertAtHead(3)
+
+    fmt.Println(lk.Values()) //[]int{3, 2, 1}
+}
+```
+
+
+
+
+### <span id="DoublyLink_InsertAtTail">InsertAtTail</span>
+<p>Insert value into doubly linklist at tail(last) index</p>
+
+<b>Signature:</b>
+
+```go
+func (link *DoublyLink[T]) InsertAtTail(value T)
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    link "github.com/duke-git/lancet/v2/datastructure/link"
+)
+
+func main() {
+    lk := link.NewDoublyLink[int]()
+
+    lk.InsertAtTail(1)
+    lk.InsertAtTail(2)
+    lk.InsertAtTail(3)
+
+    fmt.Println(lk.Values()) //[]int{1, 2, 3}
+}
+```
+
+
+
+### <span id="DoublyLink_DeleteAt">DeleteAt</span>
+<p>Delete value into doubly linklist at index, index shoud be great or equal 0 and less or less than number of link nodes - 1</p>
+
+<b>Signature:</b>
+
+```go
+func (link *DoublyLink[T]) DeleteAt(index int) error
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    link "github.com/duke-git/lancet/v2/datastructure/link"
+)
+
+func main() {
+    lk := link.NewDoublyLink[int]()
+
+    lk.InsertAtTail(1)
+    lk.InsertAtTail(2)
+    lk.InsertAtTail(3)
+    lk.InsertAtTail(4)
+
+    err := lk.DeleteAt(3)
+
+    fmt.Println(err) //nil
+    fmt.Println(lk.Values()) //[]int{1, 2, 3}
+}
+```
+
+
+
+### <span id="DoublyLink_DeleteAtHead">DeleteAtHead</span>
+<p>Delete value in doubly linklist at first index</p>
+
+<b>Signature:</b>
+
+```go
+func (link *DoublyLink[T]) DeleteAtHead() error
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    link "github.com/duke-git/lancet/v2/datastructure/link"
+)
+
+func main() {
+    lk := link.NewDoublyLink[int]()
+
+    lk.InsertAtTail(1)
+    lk.InsertAtTail(2)
+    lk.InsertAtTail(3)
+    lk.InsertAtTail(4)
+
+    err := lk.DeleteAtHead()
+    
+    fmt.Println(err) //nil
+    fmt.Println(lk.Values()) //[]int{2, 3, 4}
+}
+```
+
+
+
+
+### <span id="DoublyLink_DeleteAtTail">DeleteAtTail</span>
+<p>Delete value in doubly linklist at last index</p>
+
+<b>Signature:</b>
+
+```go
+func (link *DoublyLink[T]) DeleteAtTail() error
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    link "github.com/duke-git/lancet/v2/datastructure/link"
+)
+
+func main() {
+    lk := link.NewDoublyLink[int]()
+
+    lk.InsertAtTail(1)
+    lk.InsertAtTail(2)
+    lk.InsertAtTail(3)
+
+    err := lk.DeleteAtTail()
+    
+    fmt.Println(err) //nil
+    fmt.Println(lk.Values()) //[]int{1, 2}
+}
+```
+
+
+
+
+### <span id="DoublyLink_Reverse">Reverse</span>
+<p>Reverse all nodes order in linkist</p>
+
+<b>Signature:</b>
+
+```go
+func (link *DoublyLink[T]) Reverse()
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    link "github.com/duke-git/lancet/v2/datastructure/link"
+)
+
+func main() {
+    lk := link.NewDoublyLink[int]()
+
+    lk.InsertAtTail(1)
+    lk.InsertAtTail(2)
+    lk.InsertAtTail(3)
+
+    lk.Reverse()
+    fmt.Println(lk.Values()) //[]int{3, 2, 1}
+}
+```
+
+
+
+### <span id="DoublyLink_GetMiddleNode">GetMiddleNode</span>
+<p>Get the node at middle index of linkist</p>
+
+<b>Signature:</b>
+
+```go
+func (link *DoublyLink[T]) GetMiddleNode() *datastructure.LinkNode[T]
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    link "github.com/duke-git/lancet/v2/datastructure/link"
+)
+
+func main() {
+    lk := link.NewDoublyLink[int]()
+
+    lk.InsertAtTail(1)
+    lk.InsertAtTail(2)
+    lk.InsertAtTail(3)
+
+    midNode := lk.GetMiddleNode()
+    fmt.Println(midNode.Value) //2
+}
+```
+
+
+
+### <span id="DoublyLink_Size">Size</span>
+<p>Get the number of nodes in linklist</p>
+
+<b>Signature:</b>
+
+```go
+func (link *DoublyLink[T]) Size() int
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    link "github.com/duke-git/lancet/v2/datastructure/link"
+)
+
+func main() {
+    lk := link.NewDoublyLink[int]()
+
+    lk.InsertAtTail(1)
+    lk.InsertAtTail(2)
+    lk.InsertAtTail(3)
+
+    fmt.Println(lk.Size()) //3
+}
+```
+
+
+
+### <span id="DoublyLink_IsEmpty">IsEmpty</span>
+<p>Checks if linklist is empty or not</p>
+
+<b>Signature:</b>
+
+```go
+func (link *DoublyLink[T]) IsEmpty() bool
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    link "github.com/duke-git/lancet/v2/datastructure/link"
+)
+
+func main() {
+    lk := link.NewDoublyLink[int]()
+    fmt.Println(lk.IsEmpty()) //true
+
+    lk.InsertAtTail(1)
+    lk.InsertAtTail(2)
+    lk.InsertAtTail(3)
+
+    fmt.Println(lk.IsEmpty()) //false
+}
+```
+
+
+
+### <span id="DoublyLink_Clear">Clear</span>
+<p>Clear all nodes in the linklist, make it empty</p>
+
+<b>Signature:</b>
+
+```go
+func (link *DoublyLink[T]) Clear()
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    link "github.com/duke-git/lancet/v2/datastructure/link"
+)
+
+func main() {
+    lk := link.NewDoublyLink[int]()
+
+    lk.InsertAtTail(1)
+    lk.InsertAtTail(2)
+    lk.InsertAtTail(3)
+
+    lk.Clear()
+
+    fmt.Println(lk.Values()) //
+}
+```
+
+
+
+### <span id="DoublyLink_Print">Print</span>
+<p>Print all nodes info of linklist</p>
+
+<b>Signature:</b>
+
+```go
+func (link *DoublyLink[T]) Clear()
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    link "github.com/duke-git/lancet/v2/datastructure/link"
+)
+
+func main() {
+    lk := link.NewDoublyLink[int]()
+
+    lk.InsertAtTail(1)
+    lk.InsertAtTail(2)
+    lk.InsertAtTail(3)
+    
+    lk.Print() //
+}
 ```
\ No newline at end of file