The work aims to precisely control the temperature of each section of injection molding machine barrel accurately, improve the quality of injection products, and control the temperature decoupling with the internal model decoupling control strategy. With respect to the coupling between the temperatures of each section of the barrel, based on the internal model control thought, the decoupling of the barrel temperature was done with the inverse matrix transform, and the internal model decoupling controller was designed and compared with the traditional feed forward decoupling control through the analysis. Compared with the traditional feed forward decoupling control, the internal model decoupling control strategy could control the decoupling of the barrel temperature in a better way, which could effectively improve the dynamics, anti-interference ability and robustness of the system. The design of the control scheme is simple, the adjustable parameters are few and the practicability is strong.