HgCdTe detector was used to detect the interference spectra of CO2 greenhouse gases on spaceborne greenhouse gas detection equipment. The performance of HgCdTe detector is significantly affected by operating temperature, and the detector needs to work at a constant low temperature. According to the operating temperature requirement, a temperature control system for spaceborne HgCdTe detector was designed. The system is mainly composed of temperature acquisition circuit, power-driven circuit and a main control unit based on FPGA. PID algorithm was adopted to realize precise temperature control. The experiment and application results show that the temperature control precision is better than ±0.5℃, and the temperature stability is better than ±0.1℃/s, which satisfies the on-orbit working temperature requirement of HgCdTe detector.