Since the FOG (fiber-optic gyroscope) and IMU (inertial measurement unit) are sensitive to temperatare,temperatare comtrol system must be used in the devices to guarantee the accuracy and stability.A two-stage control scheme is adopted and the paper mainly introduces the development of the second stage.The design of the temperature control system was described.Modelling of the FOG and IMU was set up and simulation was made.Genetic Algorithm (GA) was used in the control scheme.The qualifuying and ratio factors of the fuzzy PID controller was optimized.Results show that the algorithm effectively improve the performance of the temperature control system.