Laser welding experiments for QP1180 high-strength steel sheet are carried out at different welding parameters, and the microstructure, microhardness, tensile properties and bulge properties of the welding joint are investigated. The results show that tempered martensite is formed in tempered zone (soft zone) of heat affected zone, leading to the softening in this zone. Increasing welding speed and reducing heat input can significantly reduce softening degree. The soft zone is strengthened by the constraints, leading to the fracture in base metal, and the strength of the soft zone is equivalent to that of the base metal. Increasing welding speed and weld line offset can obviously improve the bulge test value of the welding sheet. The welding sheet obtained at high welding speed fractures perpendicular to the weld and has high bulge test value, and the welding sheet obtained at low welding speed fractures parallel to the weld along the soft zone and has low bulge test value. Bulge test value improves gradually as the weld line offset increases and approaches to that of the base metal when the offset reaches to 30 mm.