The thin nickel based sheet used in stator and rotor cans of a nuclear main pump is welded by laser and arc. In order to evaluate the effect of different welding technology on the welding quality of cans, the mechanical properties of laser welded joint and argon arc welded joint of can materials are compared and analyzed. Radiographic testing and penetrant testing are used to confirm whether defects exist in welded joints. And tensile experiment and bending experiment of flawless welded joints are carried out. The results show that when ensuring welded joints have good appearance and minimum reinforcement,perfect weld surface can be obtained by both laser welding and arc welding. But radiographic testing shows that the welds obtained by laser welding are evener and the weld with is narrower. The tensile properties of welded joints obtained by laser welding and arc welding are both better than that of base metal. The tensile property of laser welded joints is equivalent to that of arc welded joint. There are no cracks detected in the welded joints after bending experiment.