Temperature unstability is one of the important factors affecting the performance of an uncooled infrared focal plane detector. A MAX1978-based temperature control system with a closed-loop control structure is designed. The control system drives a thermoelectric cooler module via an external proportional-integral-derivative compensation network and the temperature of the detector is controlled. The experimental result shows that the system can effectively control the temperature of the focal plane detector with an accuracy of 0.06℃.