Abstract: Following the problem of driving method for the spherical motion mechanism, a new type of hydraulic drive spherical joint was designed. Driven by a full cycle rotating motor and a swing motor with rudder blade, the mechanism could rotate more than one circle. Based on the mechanism theory, the forward-inverse kinematics equations and Jacobian matrix were produced, the singular configuration of the mechanism was found. Analyzing the dexterity index and inertia force global performance index, the structure parameters of the optimum mechanism performance were found with simulation. The characteristics of the joint mechanism are compact structure, low coupling, large capacity, and the joint can complete the omni-directional output.