In order to accurately obtain the temperature field distribution characteristics of double-pulse metal inert gas (MIG) welding of aluminum alloy plates, a dynamic combined welding heat source model based on the heat distribution and weld formation characteristics of full penetration welding was proposed. Through the preparation of subroutines and the secondary development of finite element software, the spatial distribution loading of the dynamic heat source model was realized, and the weld bead morphology and temperature field distribution characteristics in the simulation process were obtained. According to the simulation process parameters, the butt-welding experiment of 2 mm-thick 6061-T6 aluminum alloy plates was carried out by double-pulse MIG welding. The weld bead morphology characteristics were obtained, the temperature data of temperature measurement points were recorded, and the thermal cycle curves of temperature measurement points were drawn. By comparing the simulation and experimental results，it is found that，for the full penetration welding of aluminum alloy sheet, the weld morphology obtained by the dynamic combined heat source model is in good agreement with the actual weld bead morphology, and the simulation error of temperature field is within the allowable range. The maximum error point appears at 20 mm away from the weld, and the maximum error is 12.25%.