In order to improve the packaging precision of quantitative packaging machine, a quantitative packaging system was designed with PLC as the controller and TPC7062KS as the operating screen based on the existing quantitative packing machine. By directly acquiring operational information and various data of the packaging system, it could improve the reliability and operability of the packaging system. Based on the analysis of the shortages of traditional methods, it adopted fuzzy PID control algorithm for closed-loop control in the ladder diagram program. The experiments showed that the packaging accuracy could reach ±0.2%. This control method can improve the precision of packaging precision and also make it hardly influenced by external factors.