diff --git a/src/main/java/com/bellszhu/elasticsearch/plugin/synonym/analysis/DynamicSynonymTokenFilterFactory.java b/src/main/java/com/bellszhu/elasticsearch/plugin/synonym/analysis/DynamicSynonymTokenFilterFactory.java
index bc6e002..3b34170 100644
--- a/src/main/java/com/bellszhu/elasticsearch/plugin/synonym/analysis/DynamicSynonymTokenFilterFactory.java
+++ b/src/main/java/com/bellszhu/elasticsearch/plugin/synonym/analysis/DynamicSynonymTokenFilterFactory.java
@@ -29,6 +29,14 @@
 import org.elasticsearch.indices.analysis.AnalysisModule;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+
 
 /**
  * 
@@ -63,8 +71,8 @@ public Thread newThread(Runnable r) {
 	private final int interval;
 
 	private SynonymMap synonymMap;
-	private Map<DynamicSynonymFilter, Integer> dynamicSynonymFilters = new WeakHashMap<DynamicSynonymFilter, Integer>();
-
+	//	private Map<DynamicSynonymFilter, Integer> dynamicSynonymFilters = new WeakHashMap<DynamicSynonymFilter, Integer>();
+	private List<DynamicSynonymFilter> dynamicSynonymFilters = Collections.synchronizedList(new ArrayList<>());
 	public DynamicSynonymTokenFilterFactory(
 			IndexSettings indexSettings,
 			Environment env,
@@ -132,8 +140,7 @@ protected TokenStreamComponents createComponents(String fieldName) {
 	public TokenStream create(TokenStream tokenStream) {
 		DynamicSynonymFilter dynamicSynonymFilter = new DynamicSynonymFilter(
 				tokenStream, synonymMap, ignoreCase);
-		dynamicSynonymFilters.put(dynamicSynonymFilter, 1);
-
+		dynamicSynonymFilters.add(dynamicSynonymFilter);
 		// fst is null means no synonyms
 		return synonymMap.fst == null ? tokenStream : dynamicSynonymFilter;
 	}
@@ -150,8 +157,7 @@ public Monitor(SynonymFile synonymFile) {
 		public void run() {
 			if (synonymFile.isNeedReloadSynonymMap()) {
 				synonymMap = synonymFile.reloadSynonymMap();
-				for (DynamicSynonymFilter dynamicSynonymFilter : dynamicSynonymFilters
-						.keySet()) {
+				for (DynamicSynonymFilter dynamicSynonymFilter : dynamicSynonymFilters) {
 					dynamicSynonymFilter.update(synonymMap);
 					logger.info("success reload synonym");
 				}