The temperature field and residual stress field is the main problem of the research in the process of welding of aluminium alloy.First we define finite element model, using 3 d finite element grid partition technology and realize grid division, Second we define a one-dimensional series array, using the "*do"command of APDL language programming to realize the indirect load of the weld in simulation of the welding process, which can simulate the dynamic process of welding.Through temperature field and residual stress field of calculation, get the main path along the temperature and the residual stress distribution curve, get 5052 aluminum alloy temperature field and residual stress of distribution.The finite element analysis of the law applied to the aluminum alloy plasma welding process, the welding quality was obviously improved.