This paper introduces the technology characteristic and control requirement of Liquid milk sterilization system．To solve the problems such as low precision and parameters cannot be adjusted according to the working condition which existence in the temperature PID control system ，this paper put forwards a new algorithm which combine fuzzy control with traditional PID control, to optimize the traditional PID temperature control system. This fuzzy control algorithm is realized by Siemens PLC based on the method of lookup table. In order to test the performance of this system, simulation experiments are carried out base on MATLAB. the result shows that the parameter selftuning fuzzy PID control compared to the classic PID control the liquid milk sterilization system has higher control accuracy, faster response speed and, better robustness.