diff --git a/manager/src/main/java/org/apache/hertzbeat/manager/service/impl/TagServiceImpl.java b/manager/src/main/java/org/apache/hertzbeat/manager/service/impl/TagServiceImpl.java
index 1a18450d3ce..a663c93efc4 100644
--- a/manager/src/main/java/org/apache/hertzbeat/manager/service/impl/TagServiceImpl.java
+++ b/manager/src/main/java/org/apache/hertzbeat/manager/service/impl/TagServiceImpl.java
@@ -24,6 +24,7 @@
 import java.util.stream.Collectors;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.collections.CollectionUtils;
+import org.apache.commons.lang3.StringUtils;
 import org.apache.hertzbeat.common.entity.manager.Monitor;
 import org.apache.hertzbeat.common.entity.manager.Tag;
 import org.apache.hertzbeat.manager.dao.TagDao;
@@ -55,6 +56,7 @@ public void addTags(List<Tag> tags) {
     public void modifyTag(Tag tag) {
         Optional<Tag> tagOptional = tagDao.findById(tag.getId());
         if (tagOptional.isPresent()) {
+            tag.setTagValue(StringUtils.isEmpty(tag.getTagValue()) ? null : tag.getTagValue());
             tagDao.save(tag);
         } else {
             throw new IllegalArgumentException("The tag is not existed");