Temperature plays a vital role in the laser cutting glass substrate process. To know the dynamic distribution of temperature and improve the cutting quality, a simulation method for temperature field is proposed. The three-dimensional finite element analytic model of the CO2 laser thermal stress in cutting electronic strengthened glass is put forward and the temperature field is analyzed in finite element analysis software ANSYS. The changes of temperature field with different parameters and the effects on the cutting quality are studied. The relations between distribution of temperature and parameters including laser power, spot size and scanning speed are obtained. Certain guidance in selection of parameters in actual process is manifested.