Abstract: In order to improve the pumping efficiency and make the temperature distribution more uniformity, a V-shape active mirror heat capacity laser was set up.Heat distribution of the laser medium was studied with numerical simulation and experimental methods.In numerical simulation, asymmetry of inner heat source was sufficiently considered, and in three-dimension heat distribution was analysed.In experiment, the temperature on the surface of the laser medium was measured by a thermal imaging system.The result of numerical simulation and experimental measurement were quite identical.It is demonstrated that the shape of the heat capacity has great advantage on improving thermal distribution.