Aming at low precision and weak robust of the temperature control in the quenching process of round link chain, this paper puts forward a new quenching system for round link chain which is based on expert PID controller. The paper describes the principle and implementation method of expert PID controller, applies the algorithms into the quenching system for round link chain, and compares the effect of the common PID and expert PID controller. The experiment results show that the quenching system for round link chain based on expert pid controller system can achieve good control of round link chain quencher temperature and hold the advantages of fast response and strong robustness.