diff --git a/skynet-src/skynet_server.c b/skynet-src/skynet_server.c
index 0a3a6b00..5464c12b 100644
--- a/skynet-src/skynet_server.c
+++ b/skynet-src/skynet_server.c
@@ -169,7 +169,11 @@ skynet_context_new(const char * name, const char *param) {
 int
 skynet_context_newsession(struct skynet_context *ctx) {
 	// session always be a positive number
-	int session = (++ctx->session_id) & 0x7fffffff;
+	int session = ++ctx->session_id;
+	if (session <= 0) {
+		ctx->session_id = 1;
+		return 1;
+	}
 	return session;
 }