This paper mainly adopted a hybrid molecular dynamics simulation method with the classical diffusion theory, in order to reveal the micro-scale diffusion characteristics of the welding interface, the molecular dynamics simulation of the explosive welding interface of shape memory alloy Ni50Ti50 and Cu was carried out by means of the embedded potential function (EAM potential). The micro-morphology and physical characteristics of the explosive welding interface were analyzed by means of SEM and EDX. The pressure oscillation of Ni50Ti50-Cu alloy system becomes smaller and smaller under the impact condition of uz=1500 m/s and ux=700 m/s. The temperature of the system is about 1350 K and the pressure is about 28GPa after 120ps. The atomic concentration of Cu on both sides of the diffusion layer is about 5% and that of Ni and Ti is about 5%. The interfacial diffusion layer thickness ranged from 1.03 to 1.45um. The thickness of the interfacial diffusion layer was about 1.56um, which was verified to the results of the SEM and EDS.