diff --git a/src/serial_code/hail.rs b/src/serial_code/hail.rs
index 6fcbb34..d349f78 100644
--- a/src/serial_code/hail.rs
+++ b/src/serial_code/hail.rs
@@ -69,13 +69,6 @@ impl HailSerialCodeAlgorithm {
         current_time - *HAIL_PERIOD_START
     }
 
-    /// 判断指定时间戳是否比已经存储的最后一次使用的时间戳要大。否则时间发生了回拨。
-    fn validate_timestamp(&self, timestamp: i64) -> bool {
-        let last_timestamp = self.last_timestamp.clone();
-        let last_timestamp = last_timestamp.lock().unwrap();
-        timestamp >= *last_timestamp
-    }
-
     /// 生成一个64位长整型序列ID。
     pub fn generate_serial(&self) -> i64 {
         let last_timestamp = self.last_timestamp.clone();
@@ -93,7 +86,7 @@ impl HailSerialCodeAlgorithm {
                     std::thread::sleep(time::Duration::from_secs(1));
                     continue;
                 }
-            } else if !self.validate_timestamp(timestamp) {
+            } else if timestamp < *last_timestamp {
                 std::thread::sleep(time::Duration::from_secs(1));
                 continue;
             }