Electromechanical gyro is one of the key components in inertial navigation systems, which directly influences the system precision. As the working temperature varies, the change of rotor supporting voltages can result in the drift of the gyro, which can cause measurement errors. Therefore, the temperature control should be stringent especially for inertial navigation devices due to its long working hours and high precision requirement. A high precision temperature control system has been developed with digital circuits which use the integrated temperature ADT7410 to measure temperature. A single-chip micro-computer ADuc845 has been utilized to realize fuzzy self-turning PID control. The MODFET has been applied to the heater element (a stripe of flexible resistance) to achieve the switch control. The experimental results indicate that this temperature control system is able to maintain the gyro temperature within ±0.04 °C when the variation in the ambient temperature is no more than ±1 °C.