Deployment of buoy systems is one of the most important procedures for buoy system’s operation. In this paper, buoy system with surface buoy, cable segments with components, anchor and so on is modeled by applying multibody dynamics method. Then numerical method is used to solve the ordinary differential equations and dynamics simulations are achieved while anchor is casting from board. The trajectories, velocity and acceleration of different nodes in buoy system are obtained. The transient tension force of each part of cable is analyzed in the process of deployment. This work is helpful for design and deployment planning of buoy system.