diff --git a/lib/index.d.ts b/lib/index.d.ts
new file mode 100644
index 0000000..08e8332
--- /dev/null
+++ b/lib/index.d.ts
@@ -0,0 +1,5 @@
+declare module 'compute-lcm' {
+    declare export type ElPickCallback = (el: any, index: number) => number;
+    declare export default function lcm(a: number, b: number, ...nums: number[]): number;
+    declare export default function lcm(arr: number[], callback: ElPickCallback):  number | null;
+}