Based on pre-processing software and post-processing software,the numerical simulation and experimental comparison of the temperature field of the three arc welding processes of thick copper plates are carried out. First use the pre-processing software to perform modeling and meshing,and then use the post-processing software to complete the welding simulation process. This study mainly uses postprocessing software to adjust welding current,arc voltage,distance between welding guns,welding speed,wire feeding speed and other process parameters to simulate the welding temperature field of thick copper plate under multiple sets of process parameters. Then,the welding temperature field nephogram of different welding parameters is compared and analyzed,in order to obtain the best welding parameters（Welding distance of 16 mm,welding current 300 A,TIG welding gun voltage is 16 V,MIG welding gun voltage is 20 V,MIG welding torch wire speed of 10 mm/s）. The simulation results are as follows: the melting distance of MIG welding torch is 6.4 mm,the penetration depth is 4.8 mm,the length of molten pool is 12.6 mm.