Dual-phase steel DP590 and aluminum alloy 6061 sheet was welded through pulsed laser welding technology, in a form of lap joints.The microstructure, element distribution and mechanical properties of the welded joint were measured and analyzed. The test results show that the lap joint of DP590 duplex steel and 6061 aluminum alloy sheet can be welded by using laser pulse welding technology. The weld zone is mainly columnar crystal structure with coarse grain, and the heat affected zone is martensite with fine and uniform grain and ferrite with continuous distribution.The maximum hardness (3 N test force) of the steel side is 440.1 HV in the heat affected zone, and the maximum hardness of the aluminum side is 325.4 HV in the weld zone. The maximum tensile strength of the joints is 35.0 MPa. The fracture postions of the joints are mainly two situations in the following. It directly fracturesfrom the weld interface in the shallow deep joints or near the aluminum side of the fusion line in the deep welding joints.