Abstract: The solid heat capacity laser needs cooling after continuous operation for a short time before the next operation, so the cooling speed directly affects its working efficiency. The Nd: GGG disk laser medium end symmetrically pumped from four directions by the diode arrays was adopted. Based on the heat transfer equation with heat depositing mode, the numerical simulations of the temperature field and the thermal stress distribution in the slab medium were performed under the condition of heat capacity operation by finite element analysis method. Four cooling methods, including cold gas, water cycle, atomization and phase cooling, were respectively used to cool the slab medium. The transient temperature history and the stress history of the medium were simulated. The simulation result indi