Cable-driven parallel manipulator (CPM), in which cables are used to replace links to manipulate objects, is developed from parallel and serial cable driven manipulator. Compared with the parallel manipulator, this kind of manipulator has more advantages. The cooperative variation of lengths of the six long cables pulls the feed cabin to track radio source with 6 DOFs. Similar to a parallel manipulator, the cable-driven system for five-hundred meter aperture spherical radio telescope (FAST) is viewed as a CPM. According to its 5 m scaled model, the relationship between end forces and cable length is derived based on the analytical equation of catenary of a cable with two endpoints fixed. So the actuating forces on the cabin locating at a certain position and pose can be solved with the given driving cable lengths. Secondly, based on the inverse kinematics analysis the inverse dynamic formulation of CPM is established by using Lagrange's equations. Finally, the dynamic modeling can be justified by the example.