Abstract:This paper introduces the main constitution, the method of software and hardware structure realization of a medical infusion heating system. The system is based on AT89C52 single-chip microcomputer and adopts the integral-separated PID increment arithmetic algorithm combined with Pulse Width Modulation (PWM). The application programs of the system is composed of structured models. The application result shows that the system is simple,reliable, easy to operate and has high controlling accuracy and short control time,which meets both the requirements of patients and hospital.