Abstract: The dissimilar steel weldes by spark plasma sintering(SPS)technology was developed in this paper.The welded joints of 45 steel and 18-8 stainless steel were obtained under different SPS parameters, and the microstructure, chemical composition, fractography and micro-hardness of the joints were examined.The influence of SPS parameters on the microstructure and properties of welding joints was studied, and the SPS welding metallurgy mechanism was also discussed.The result indicated that the new SPS technology could make effective welding in short time, low temperature and pressure, and the influence of the temperature is higher than the holding time and the pressure in the SPS procedure.