Abstract: The spacecraft New Horizons is the first spacecraft for the reconnaissance of Pluto and its satellites as well as other celestial bodies in the Kuiper Belt. The spacecraft faces with a complex and varied thermal environment in the launch, the on-orbit flight and the detection process, and its thermal control system is designed to ensure the instrument and the equipment in the appropriate temperature range of normal work. The overall design of the New Horizons is discussed, especially the thermal control design with its engineering basis, characteristics and some enlightenment.