Abstract: In order to research the effect of different nozzle shapes on the quality of weld forming joint, numerical simulation of flow field of different shape nozzles were established by FLUENT software. The testing of bead-on-plate welding to 5083 aluminum alloy plate with 10mm thickness was carried out under the same processing parameters by using Nd:YAG-MIG hybrid welding. After experimental verification, the results show that, the welding stability of multi-row round nozzle is the best, and weld penetration and weld width are the largest, 9.41mm and 4.45mm respectively, but the porosity is up to 7.34%. The protective effect of single side square nozzle is the best, but its welding stability, weld penetration and weld width are between multi row round nozzle and single side round nozzle. Protection effect of single side round nozzle is between multi row round nozzle and single side square nozzle, and then, welding stability and characteristic value of welding appearance have the worst results. Protection effect of square nozzle is the best. The research illustrates numerical simulation of protection effective range and airflow stiffness of different nozzle shapes.