The invention discloses a large drawing-force positioning winch of ship, which comprises the systems as power, shift, cylinder group, row wire, ratchet wheel brake, quick-drawing, constant tension and control. Wherein, the shift system comprises a planet power shift device and a power dual-dividing device; the planet power shift device is mounted with a motor, a coupler, two shift brakes, a high-speed brake and two planet supports, while the first planet support is connected to the second sun wheel; the first gear ring is connected to the second gear ring; the coupler is connected to the high-speed brake; the first shift brake is connected to the second planet support; the second shift brake via the coupler is connected to the first planet support; the output of first planet support is mounted with the second gear ring and the output big gear wheel; the power dual-dividing device is mounted with a gear wheel axle, a transmission gear wheel, two branch gear transmission devices and water-cooling brake that meshed with output big gear wheel; the water-cooling brake is connected to the gear wheel axle and the transmission gear wheel to realize damping brake. The inventive winch can work on marine with high efficiency, high support ability, anti-impact ability and shortened construction time.