The work aims to propose a method of improving the control accuracy and stability of heat sealing temperature of food packaging machine, in order to improve the bag shape quality and heat sealing quality of food packaging products. In view of the poor stability and accuracy of the temperature control system of plastic film heat sealing in food packaging, which caused the quality problems of packaging materials such as excessive shrinkage and improper sealing, a double fuzzy controller was designed to tune the PID parameters online. When the temperature deviation was large, the fuzzy controller 1 was used for rough tuning to achieve faster dynamic response. When the temperature deviation was small, the fuzzy controller 2 was used for fine tuning to achieve better steady-state accuracy. The double fuzzy PID controller was compared with the traditional PID and the fuzzy PID controller by simulation. The simulation results of Matlab showed that, the double fuzzy PID controller had the advantages of fast regulation speed, strong robustness and small overshoot, and it could effectively improve the control accuracy and stability of the control system. The double fuzzy PID controller has strong self-adaptive ability. It can overcome the non-linear and time-varying characteristics of the temperature control system of heat sealing of food packaging machine, and realizes the fast and stable regulation of the heat sealing temperature of the packaging machine. Experiments show that, the temperature deviation of heat sealing is controlled within ±1.5 ℃, which improves the quality of food packaging and the automation level of equipment to a certain extent.