Based on the theory of heat conduction, a two-dimensional axisymmetric thermal model was established for the temperature field characteristics of aluminum alloy irradiated by a combination of millisecond pulse and continuous laser. The process of laser irradiating aluminum alloy was numerically simulated by finite element method, and the temperature field distribution and variation rule of laser irradiating aluminum alloy surface under different loading time interval and different spot radius were obtained. The results show that the temperature of target center increases with the increase of laser loading time interval. At the end of the pulse laser irradiation period, the temperature of the target radiated by the continuous laser will increase significantly. The temperature field of aluminum alloy irradiated by combined laser is mainly determined by continuous laser, but the temperature of the center point of the target can be increased appropriately if appropriate pulse laser parameters are selected, especially when the power density of pulse laser is greater than 8.8×104 W/cm2.