Force controllable workspace （FCWS） and system stiffness are important performance of cable-driven parallel system. When the center of mass of movable platform deviates from its centroid position， extra torque will be generated， which adversely affects the performance of cable-driven parallel system. To reduce the adverse effects caused by centroid bias， a new cable layout is proposed for the 36-cable 6-DOF cable-driven parallel system， and the dynamics equation of the redundant cable-driven parallel system is solved by the classified minimum variance optimization. Then the FCWS is calculated and the adverse effects of each group of cables on FCWS at each point in space are analyzed， and the theoretical static stiffness of the cable-driven parallel system is calculated. According to whether the center of mass is biased or not， the advantages and disadvantages of the typical layout and the new layout in the cable-driven parallel system are compared and analyzed. The results show that when the center of mass is in the centroid， there is little difference in FCWS between the two layouts. When the center of mass is biased， the FCWS of the cross layout is about 31.9% higher than that of the typical layout， and the translational stiffness of the two layouts is not much different， while the torsional stiffness of the cross layout is significantly higher than that of the typical layout， which verifies the effectiveness of the new layout in improving the system performance. The conclusion can provide some reference for the structure layout of the cable-driven parallel system.