The models of temperature and thermal stress distribution in optical material irradiated by a laser pulse are researched theoretically.Based on the pulse characteristics,the temperature distribution models for long pulse and short pulse are built respectively,and on this basis,thermal stress distribution model is further set up.Taking fused silica as an example,the temperature and thermal stress distribution are calculated and analyzed.The results indicate that the temperature distribution profiles at the end of the pulse are same for long pulse and short pulse model.The theoretical analysis shows that the temperature near the spot center reaches the melting point or vapor point of fused silica,which leads to a melt damage or evaporation damage.The temperature rise in the focal areas is nonuniform,which leads to thermal stress.The thermal stress is greater than the fracture strength of sample,which induces the damage,such as thermal cracks.