In order to improve the quality of glass cut by laser controlled fracture method, the temperature change of material after 6.45μm laser irradiation was studied. The temperature distribution of glass irradiated by 6.45μm laser was calculated by using the continuous laser output power, and the correctness of the model was verified by experiments. Temperature field of glass heated by 6.45μm laser and 10.6μm laser under the same laser parameters was simulated and compared. The smooth and crack-free cutting samples were obtained by experiment. The results show that, the surface temperature of 6.45μm laser is below than that of 10.6μm laser. 6.45μm laser can obtain high quality cutting face by hot cracking. The research is helpful for the modeling and the optimization of mid infrared laser glass cutting.