Abstract: The contact-impact dynamics in the course of spacecraft docking is the basis of research and design of docking mechanism of manned-space vehicle. According to the docking mechanism of androgynous and peripheral type, a contact-impact dynamic model and an explicit expression of impact load are given in this paper by using the vector mechanics and visco-elasticity. The targeting calculation and statistical analysis of an engineering sample is used to illustrate the method, and a satisfying result is obtained.