Abstract: Due to large difference in physical and chemical parameters of copper/steel, there are problems of brittleness and stress concentration of joint during fusion brazing. In this study, the copper/steel welded joints were obtained by using new electromagnetic pulse welding technology with designed taper or step lap forms. By using the interface microscopic SEM, EDS observation and microhardness test, the connection characteristics of joints with different lap forms were analyzed. The results show that when the direct lap form is used, it has poor waveform and a few pores.When the step lap form is used, the interface waveform is large, but there are front and back vortices and “fusion zone“ at the interface. The interface prepared by using taper lap form is an approximate homogeneous wave connection. When the designed taper structure is used, the width of diffusion zone of the wavy interface is 5 μm, and the two materials are closely bonded. The plastic deformation of the interface and the degree of element diffusion determine the hardness distribution of the interface. In the taper lap form, the metal particle flow can effectively fly out of the interface, the produced plastic deformation is relatively small, and the hardness transition is gentle, which is conductive to metallurgical bonding.