The cavity deformation can lead to the decline in the laser output power and the beam quality deterioration when the laser operates, so the performance enhancement of the high power laser is restricted greatly. The heat deformation based on the heat absorption of the laser cavity and the lens pressure deformation based on cooling fluid are analyzed, the method of the heat pipe cooling cavity mirror is proposed. The principle of the heat pipe cooling and the advantage of heat pipe in heat conductivity are introduced, the solution of heat pipe cooling cavity mirror is designed, which provides the effective way to effectively control the lens surface deformation of the high power laser system.