In order to improve the quality of laser filler wire brazing between the top and side panels of the car body,the heat conduction law of brazing was studied,and a butt joint model of galvanized steel sheet was established.CuSi3 was used as the brazing filler metal for numerical simulation analysis.Under the premise of variable latent heat and thermal convection,the double ellipsoid laser heat source model is used for thermal analysis.The law of the temperature of laser wire filler brazing over time has been explored,the sensitivity of different regions to temperature and the temperature field distribution of the weld pool under different powers are explored,providing a theoretical model for laser wire filler brazing and further exploration of brazing formation quality has a driving effect.