To meet certain control requirements of a passive protection system of the platform attitude, this paper proposes a novel cable-parallel manipulator and designs a control system for the manipulator. Establishes two coordinate system, one is fixed on the static platform and the other one fixed on moving platform. Uses spherical coordinates and Euler angles to indicate the attitudes of the moving platform respectively, and then gives the transformational relationship between them. This method builds on the PID control model of cable length by analyzing inverse kinematic solution, and changes the length of the rope on the basis of the motor rotational angle. After that, the software of the control system and its hardware which is based on DSP are designed according to the established model and the control requirements. Finally, a series of experiments and simulations verify that: each module of the control system is stable, and the control model is also correct, the design meets the control requirements and realize the expected function.