In order to investigate the thermal effect of moving quartz glass heated by CO2 laser, a mathematical model was established as the influence of irradiation and convection was considered. The temperature distribution was obtained using the software ANSYS. The relationships between temperature and velocity and laser parameters (power and radius) were obtained by comparing the temperature distribution for different velocity and laser parameters. The results show that the surface temperature of quartz glass increases when the laser power increases, the laser focus decreases and the speed of the quartz glass decreases.