This paper briefly introduces the current trend of laser welding of high silicon aluminum alloy at home and abroad, and introduces the analysis process of ANSYS laser welding finite element simulation in detail. The process of temperature field analysis is introduced from the aspects of heat source loading, element birth and death technique and transient thermal analysis. The temperature field distribution cloud map is obtained by ANSYS postprocessor. The instant-aneous stress distribution of welding is obtained by thermal structure coupling process. The temperature field obtained by simulation meets the requirements of welding temperature,and the stress field distribution will produce some deformation.