diff --git a/src/main/java/cloud/tianai/captcha/template/slider/generator/impl/CacheImageCaptchaGenerator.java b/src/main/java/cloud/tianai/captcha/template/slider/generator/impl/CacheImageCaptchaGenerator.java
index b22e8f1..883da20 100644
--- a/src/main/java/cloud/tianai/captcha/template/slider/generator/impl/CacheImageCaptchaGenerator.java
+++ b/src/main/java/cloud/tianai/captcha/template/slider/generator/impl/CacheImageCaptchaGenerator.java
@@ -113,7 +113,7 @@ public class CacheImageCaptchaGenerator implements ImageCaptchaGenerator {
             return target.generateCaptchaImage(generateParam);
         }
         // 减1
-        if (poll == null) {
+        if (poll != null) {
             AtomicInteger pos = posMap.get(generateParam);
             if (pos != null) {
                 pos.decrementAndGet();