Laser Lap Welding of industrial pure nickel NI201 was studied by using high power Nd:YAG laser and welding robots. The formation and mechanical properties of welded joints was analyzed by optical microscopes, microhardness tester, tensile testing machine, scanning electron microscopy. The influence of welding parameters on the formation and mechanical properties of joints was studied. From the experimental results, it is found that the fine macro-morphology of lap laser welded joint was appeared. Microhardness is different in different zone of laser lap welding joint, the minimum tensile strength of laser lap welding is 389.5 MPa, which is 92% of the base metal. Furthermore, laser power and welding speed has a great influence on macro profile, formation and mechanical properties.