In this paper,contact brazing technique was used to weld nickel and copper on the surface of stainless steel,and Mg powder was added as the intermediate reaction layer for brazing. The connection between 3003 aluminum alloy and stainless steel was carried out. The mechanical properties of welded joints were measured by universal testing machine. The microstructures and element distributions of the joints were observed by scanning electron microscopy（SEM）. The interface morphology,phase composition and connection mechanism were analyzed. When the brazing temperature is 560 ℃ and welding pressure is 0.1 MPa,effective connection holding time is 15 min for contact reactive brazing of the two joints the maximum shear strength of 23.1 MPa,the average shear strength of 21.6 MPa,filler metal Al atom diffusion is obvious,and the formation of Al-Mg,Al-Cu,Al-Fe and other intermetallic compounds.