In order to solve the challenges of low precision, over-reliance on expert experience in temperature controlling system of infrared target simulation device, a fuzzy PID method is designed based on improved GA algorithm optimization in temperature controlling system of infrared target simulation device. The system adopts the improved GA algorithm with auto-adaptive crossover probaility and mutation probability. It optimizes the quantization factor and scale factor of fuzzy PID controller, and completes the adaptive adjustment of PID parameters and determines the optimal solution of the temperature controlling unit. The simulation model of temperature controlling system is established in Simulink and verified by simulation. Compared to the fuzzy PID controller, the improved GA algorithms optimizes fuzzy PID controller shortened the adjustment time by 34.84%, the overshoot by 63.75% and the steady-state error by 66.67%. It shows that the improved GA algorithms optimized fuzzy PID controller can improve the control performance of the system.