diff --git a/src/lib/stock-api.ts b/src/lib/stock-api.ts
index 930d064..0d3825a 100755
--- a/src/lib/stock-api.ts
+++ b/src/lib/stock-api.ts
@@ -97,7 +97,9 @@ export interface BoardInfo {
  * - 8/4/920开头：北交所（BJB）
  * - 其他：主板
  */
-export function getStockBoard(code: string): BoardInfo {
+export function getStockBoard(code: string | null | undefined): BoardInfo {
+  // 题材列表等场景下 securityCode 可能为 null（无领涨股的题材），兜底为主板
+  if (!code) return { board: "main", label: "", className: "" };
   if (code.startsWith("688")) {
     return { board: "kcb", label: "科", className: "bg-red-500/10 text-red-500 border-red-500/30" };
   }
diff --git a/src/lib/theme-api.ts b/src/lib/theme-api.ts
index ac44ae6..88d9b6b 100644
--- a/src/lib/theme-api.ts
+++ b/src/lib/theme-api.ts
@@ -6,8 +6,8 @@ import { getApiBaseUrl } from "@/lib/api-client";
 export interface ThemeItem {
   themeCode: string;
   themeName: string;
-  securityName: string; // 领涨股名称
-  securityCode: string; // 领涨股代码
+  securityName: string | null; // 领涨股名称（无领涨股的题材为 null）
+  securityCode: string | null; // 领涨股代码（无领涨股的题材为 null）
   codeWithSuffix: string;
   hotRank: number; // 热度排名
   f3: number | null; // 领涨股涨幅
diff --git a/tests/_stub-api-client.cjs b/tests/_stub-api-client.cjs
new file mode 100644
index 0000000..2dc2bf2
--- /dev/null
+++ b/tests/_stub-api-client.cjs
@@ -0,0 +1,5 @@
+// stub：getStockBoard 测试用，仅用于解析 @/lib/api-client 别名（CommonJS）
+function getApiBaseUrl() {
+  return "http://localhost:8000";
+}
+module.exports = { getApiBaseUrl };
diff --git a/tests/get-stock-board-repro.mjs b/tests/get-stock-board-repro.mjs
new file mode 100644
index 0000000..8892ff0
--- /dev/null
+++ b/tests/get-stock-board-repro.mjs
@@ -0,0 +1,63 @@
+// 最小复现/验证脚本：直接编译 src/lib/stock-api.ts 真实源码，
+// 调用 getStockBoard(null)，复现「Cannot read properties of null (reading 'startsWith')」。
+// 无测试框架，node 直接运行：node tests/get-stock-board-repro.mjs
+import fs from "node:fs";
+import path from "node:path";
+import Module from "node:module";
+import ts from "typescript";
+
+const srcPath = path.resolve("src/lib/stock-api.ts");
+const source = fs.readFileSync(srcPath, "utf8");
+
+const js = ts.transpileModule(source, {
+  compilerOptions: { module: ts.ModuleKind.CommonJS, target: ts.ScriptTarget.ES2020, esModuleInterop: true },
+}).outputText;
+
+const mod = new Module(srcPath);
+mod.filename = srcPath;
+mod.paths = Module._nodeModulePaths(path.dirname(srcPath));
+
+// 拦截 @/lib/api-client 别名导入（getStockBoard 本身不依赖它）
+const origResolve = Module._resolveFilename;
+Module._resolveFilename = function (request, ...args) {
+  if (request === "@/lib/api-client") return path.resolve("tests/_stub-api-client.cjs");
+  return origResolve.call(this, request, ...args);
+};
+
+try {
+  mod._compile(js, srcPath);
+} finally {
+  Module._resolveFilename = origResolve;
+}
+
+const { getStockBoard } = mod.exports;
+
+// ---- 断言 ----
+function assertThrows(fn, label) {
+  try {
+    fn();
+    console.log(`✗ ${label}: 未抛错`);
+    process.exitCode = 1;
+  } catch (e) {
+    console.log(`✓ ${label}: 抛错 -> ${e.message}`);
+  }
+}
+
+function assertNoThrow(fn, label) {
+  try {
+    const r = fn();
+    console.log(`✓ ${label}: 未抛错 -> ${JSON.stringify(r)}`);
+    return r;
+  } catch (e) {
+    console.log(`✗ ${label}: 抛错 -> ${e.message}`);
+    process.exitCode = 1;
+  }
+}
+
+// 正常代码
+assertNoThrow(() => getStockBoard("600000"), "正常代码 getStockBoard('600000')");
+// 崩盘场景：securityCode 为 null（East Money 题材列表实测存在），修复后应兜底返回主板
+assertNoThrow(() => getStockBoard(null), "null securityCode");
+assertNoThrow(() => getStockBoard(undefined), "undefined securityCode");
+// 空串不崩
+assertNoThrow(() => getStockBoard(""), "空串 getStockBoard('')");