Abstract: Based on the coupling characteristics of ship rolling motions,a 3-SRR/SRU 3-DOF coupling parallel mechanism is used as ship-based stabilized platform to achieve the goal of using three-axis drivers of stabilized platform to compensate five-axis motions of the moving platform.Degrees-of-freedom and the motion characteristics of the mechanism are analyzed based on screw theory,and the rationality of input joints choosing is discussed.By using the method of equivalent motion of coordinate,coupling motion constraint equations of the mechanism are established,and position solution and workspace are given.In this paper,3-SRR/SRU 3-DOF coupling parallel mechanism is used for five-axis compensation of the ship-based stabilized platform,which enriches the application area of lower-mobility parallel mechanism.