Abstract: Based on the model of parallel mechanism antenna pedestal with configuration of 3UPS-U, the DOFs of this mechanism are calculated. By establishing the coordinate system of the movable platform and the static platform of the pedestal, the transformation matrix is determined and the equation of the inverse position is solved. In terms of the difficult problem of the forward position solution, an equation set which uses the constraint condition of the orientation cosine transformation matrix and the constraint equation of the length of the three rods is constructed, and the closed-form solution of this equation set is obtained. Based on the special geometric characteristic of the pedestal, the Jacobian matrix, forward velocity solution and inverse velocity solution are derived. Based on the theoretical model, the numerical simulation which combines the specific parameters is performed in order to obtain the inverse position solution and the inverse velocity solution. This research lays a foundation for further theoretical study and provides theoretical support for further engineering application.