In order to improve the welding quality of dissimilar steel materials, nickel coating was added as the middle layer of the base metal. Using DP590 dual phase steel and 304 stainless steel as base materials, Nd: YAG laser was used to carry out laser splicing welding of the dissimilar steel materials. The microstructure, hardness, mechanical properties and corrosion resistance of the weld were studied by means of optical microscope, scanning electron microscope and tensile testing machine. The results show that the addition of nickel coating improves the content of Ni element in the weld compared with the no nickel coating dissimilar weld, which is beneficial to the formation of lath martensite in the weld. The average hardness of the weld area is increased by 12%, and the tensile strength is higher than 370 MPa. The corrosion rate of the weld can be slowed down and the corrosion resistance of the weld can be improved by increasing the nickel coating.