A design scheme of carrying mechanism applying 6-cable-driven parallel robot is proposed based on the actual requirements of the outside wall maintenance and cleaning of a high-rise building. The spatial parallelogram structure is adopted to construct the cable-loop, and 4 motors are used to drive 6 cables, which can achieve the movement requirements of the carrying mechanism in both horizontal and vertical directions. The kinematics model of cable-loop driven parallel robot is established. The law of length variation of 6 cables is analyzed. The research lays a theoretical foundation for achieving motion control of the cable-loop parallel robot.