Abstract: It is very important for a solid laser system to have a well operating water cooling system.In our system,a inner water cooling system directly contact with solid laser rod and pumped lamp takes the heat into a heat exchanged cell to exchange the heat to outer water cooling system.The inner cooling system has the pure deionized water to increase the life time of the laser and the outer cooling system uses the ordinary water to take the heat out.The system now well operates in our lab.