A heat transmission model for YAG crystal of a side-pumping solid state laser with triangle uniform distribution was established based on heat capacity mode and considering the diode pumped light intensity distribution,specific heat capacity,thermal conductivity and the properties of YAG materials varied with temperature.The finite element method was used to simulate and analyze the temperature change of laser crystal media,analysed results indicate that YAG operated in heat capacity mode can be affected by thermal effect from asymmetric pumping light.The thermal effects of different YAGs including heat capacity model,continuous pumping and pulse pumping model were compared and analyzed,compared results show that the maximal temperature differences of the three models are 3.59、35.51 and 8.07 K,respectively,which suggests that the smallest temperature difference is at the heat capacity mode and the results can provide a reference for the design of heat capacity laser.