diff --git a/src/tsg_action.cpp b/src/tsg_action.cpp
index 3f4db6d..6293e0a 100644
--- a/src/tsg_action.cpp
+++ b/src/tsg_action.cpp
@@ -579,7 +579,7 @@ static unsigned char do_action_drop(const struct streaminfo *a_stream, Maat_rule
 static unsigned char do_action_ratelimit(const struct streaminfo *a_stream, Maat_rule_t *p_result, struct compile_user_region *user_region, enum ACTION_RETURN_TYPE type)
 {
 	struct tcpall_context *context=NULL;
-	struct leaky_bucket *bucket=create_bucket((double)((user_region->deny->bps)/1000000), user_region->deny->bps, a_stream->threadnum);
+	struct leaky_bucket *bucket=create_bucket(user_region->deny->bps, a_stream->threadnum);
 	tsg_set_bucket_to_tcpall(a_stream, &context, bucket, a_stream->threadnum);
 
 	set_ratelimit_flag(a_stream);
diff --git a/src/tsg_leaky_bucket.cpp b/src/tsg_leaky_bucket.cpp
index 6dbcaf1..41b6a93 100644
--- a/src/tsg_leaky_bucket.cpp
+++ b/src/tsg_leaky_bucket.cpp
@@ -5,26 +5,57 @@
 
 #include <MESA/stream.h>
 
+enum BUCKET_UNIT
+{
+	BUCKET_UNIT_S=0,
+	BUCKET_UNIT_MS,
+	BUCKET_UNIT_US,
+	BUCKET_UNIT_MAX,
+};
+
 struct leaky_bucket
 {
     double rate;
     int used_size;
     int bucket_size;
+	enum BUCKET_UNIT unit;
 	struct timespec refresh_time;
 };
 
+#define	BUCKET_UNIT_S_LIMIT_MAX_BIT		32*8*1024
+#define	BUCKET_UNIT_MS_LIMIT_MAX_BIT	64*8*1024
+
 void refresh_bucket(struct leaky_bucket * bucket, int thread_seq)
 {
 	long interval_us=0;
 	struct timespec end;
 	clock_gettime(CLOCK_MONOTONIC, &end);
-	interval_us = (end.tv_sec - bucket->refresh_time.tv_sec)*1000000 + (end.tv_nsec - bucket->refresh_time.tv_nsec)/1000;
 
-    bucket->used_size=bucket->used_size - interval_us*(bucket->rate);
+	switch(bucket->unit)
+	{
+		case	BUCKET_UNIT_S:			
+			interval_us=(end.tv_sec-bucket->refresh_time.tv_sec)+(end.tv_nsec-bucket->refresh_time.tv_nsec)/1000000000;
+			break;
+		case	BUCKET_UNIT_MS:			
+			interval_us=(end.tv_sec-bucket->refresh_time.tv_sec)*1000 + (end.tv_nsec-bucket->refresh_time.tv_nsec)/1000000;
+			break;
+		case	BUCKET_UNIT_US:			
+			interval_us=(end.tv_sec-bucket->refresh_time.tv_sec)*1000000 + (end.tv_nsec-bucket->refresh_time.tv_nsec)/1000;
+			break;
+		default:
+			bucket->used_size=bucket->bucket_size;
+			return ;
+	}
+	
+
+    bucket->used_size=bucket->used_size-interval_us*(bucket->rate);
     bucket->used_size=(bucket->used_size<0) ? 0 : bucket->used_size;
 
-    bucket->refresh_time=end;
-
+	if(interval_us>=1)
+	{				
+		bucket->refresh_time=end;
+	}
+	
 	return ;
 }
 
@@ -40,11 +71,31 @@ int is_permit_pass(int pkt_size, struct leaky_bucket * bucket, int thread_seq)
 	return 0;
 }
 
-struct leaky_bucket * create_bucket(double rate, int bucket_size, int thread_seq)
+struct leaky_bucket * create_bucket(int bucket_size, int thread_seq)
 {
-    struct leaky_bucket * bucket = (struct leaky_bucket *)dictator_malloc(thread_seq, sizeof(struct leaky_bucket));
+	if(bucket_size<0)
+	{
+		return NULL;
+	}
+	
+    struct leaky_bucket * bucket = (struct leaky_bucket *)dictator_malloc(thread_seq, sizeof(struct leaky_bucket));
+
+	if(bucket_size<BUCKET_UNIT_S_LIMIT_MAX_BIT)
+	{
+	    bucket->rate=(double)bucket_size;		
+		bucket->unit=BUCKET_UNIT_S;
+	}
+	else if(bucket_size<BUCKET_UNIT_MS_LIMIT_MAX_BIT)
+	{
+		bucket->rate=(double)bucket_size/(double)1000;		
+		bucket->unit=BUCKET_UNIT_MS;
+	}
+	else
+	{
+		bucket->rate=(double)bucket_size/(double)1000000;		
+		bucket->unit=BUCKET_UNIT_US;
+	}
 	
-    bucket->rate = rate;
     bucket->used_size = 0;
     bucket->bucket_size = bucket_size;
 
diff --git a/src/tsg_leaky_bucket.h b/src/tsg_leaky_bucket.h
index 42a62da..923312b 100644
--- a/src/tsg_leaky_bucket.h
+++ b/src/tsg_leaky_bucket.h
@@ -3,7 +3,7 @@
 
 struct leaky_bucket;
 
-struct leaky_bucket *create_bucket(double rate, int bucket_size, int thread_seq);
+struct leaky_bucket *create_bucket(int bucket_size, int thread_seq);
 void destroy_bucket(struct leaky_bucket **bucket, int thread_seq);
 int is_permit_pass(int pkt_size, struct leaky_bucket * bucket, int thread_seq);