One of the main goal of 5G networks is to provide ultra-reliable low latency service to users. When users keep accessing the system, the traffic in 5G core network (5GC) may be congested. Thus, we propose a load balance algorithm to select the best traffic data routing path based on the traffic loading in the 5GC. The proposed algorithm is implemented in a 5G testbed called free5GC. The experimental results show that our proposed algorithm outperforms the traditional round-robin load balance algorithm in many performance metrics.