diff --git a/docs/uni-id/cloud-object.md b/docs/uni-id/cloud-object.md
index 618a0652832a99a1d2bed00ec0ea2b58b8953184..2d8f214a79f8ea44edd6fc92ba517ea785b39fce 100644
--- a/docs/uni-id/cloud-object.md
+++ b/docs/uni-id/cloud-object.md
@@ -2113,7 +2113,7 @@ class Sign {
 
 	getSignature (params, nonce, timestamp) {
 		const paramsStr = this.getParamsString(params)
-		const signature = crypto.createHmac('sha256', `${requestAuthSecret}${nonce}`).update(`${timestamp}${paramsStr}`).digest('hex')
+		const signature = crypto.createHmac('sha256', `${this.requestAuthSecret}${nonce}`).update(`${timestamp}${paramsStr}`).digest('hex')
 
 		return signature.toUpperCase()
 	}