diff --git a/src/main/java/com/alibaba/druid/pool/DruidDataSource.java b/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
index 5f3610a6e3..2b03570a1a 100644
--- a/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
+++ b/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
@@ -531,6 +531,10 @@ public class DruidDataSource extends DruidAbstractDataSource implements DruidDat
 
         for (;;) {
             while (activeCount >= maxActive) {
+                if (estimate <= 0) {
+                    return null;
+                }
+                
                 try {
                     estimate = notMaxActive.awaitNanos(estimate); // signal by recycle
                 } catch (InterruptedException ie) {