Abstract: Aiming at the problem that the air-cooled radiator used by computer affects the smooth running of the computer and the service life of the chip, a water-cooling system for both civil and military application is designed and a water-cooled desktop computer is developed. The effect of air temperature, water temperature,the rotation speed of chassis fan and the pump power on heat dissipation of the water-cooled computer CPU is obtained by experiment and simulation under different setting conditions. In addition, the relationship between flow rate and heat resistance, pressure drop is established. Through prototype experiments for more than one year, it is found that temperature of the devices is greatly affected by the environment temperature and the water-cooled device is greatly affected by the flow rate of water, while the rotation speed of fan has little effect on the heat dissipation of various devices.