With mankind's increasing development and utilization of the ocean, underwater robot which can detect underwater environment and autonomously accomplish specific tasks has drawn great attention of researchers. Research was conducted on the kinematic and dynamical control of the underwater robot with six degrees of freedom. Firstly, considering the influences of gravity, buoyancy force, thrust and hydrodynamic force, the kinematic model and dynamical model of the underwater robot were built to describe the complicated underwater behaviors of the robot. Based on this, the dynamic model was simplified and model prediction control of the dynamics was conducted. Comprehensive comparison was also conducted on the results, which showed that model prediction control can reduce the vibration response of the system effectively.