A common problem faced in the construction of ship products is that the ship hull is made of steel structures while the superstructure is made of aluminum structures in order to reduce the ship weight and increase ship speed. The main hull and the superstructure are then welded to an aluminum-titanium-steel composite transition joint, respectively. In actual ship construction, the quality problem of the delamination of the steel-aluminum transition joint will bring great threats to the safety of the hull itself. The influence of welding heat on the steel-aluminum transition joint is studied in this paper. Firstly, the residual stress of the steel-aluminum transition joint is tested. And then the residual stress and the temperature field in the welding process of the steel-aluminum transition joint for the steel fence are calculated and analyzed by the finite element simulation method. The welding process of the steel-aluminum transition joint is also analyzed from two aspects of welding speed and welding current. The residual stress results agree well with those from the simulation results for the validity of the current simulation method. The results show that the faster the welding speed and the smaller the welding current, the lower the influence of the welding temperature..