For the balance and controlling demand of the small and flexible delivery offshore floating platform, a 2-HUS/U parallel platform was presented and it had space twodimensional stable ability, which adopt ball screw mechanism. Its HUSlimps were regarded as the driver and Ulimp was regarded as the driven. It provided a guarantee for the fast and stable balance of platform, and the degree of freedom of the platform was verified by the screw theory. According to constraint equations of platform, the reverse solution and the Jacobian matrix of the platform was derived and its velocity，acceleration performance, and reachable workspace were analyzed. The whole dynamics of space parallel platform was analyzed by the Lagrange’s formulation. The results of kinematics and dynamics analyses of parallel platform were solved as numerical example. The results show that the control of stability and balance is easily achieved by platform of less freedom. The platform has the stable ability of threewave frequency of 10°/s, and meets the stable demand of threewave angle of 10°. The maximum tilt angle of platform is 12°, and the workspace is symmetrical about the center axis. In the wave angle 45° and wave frequency 10°/s, the driving force for load is 15000N, and the platform meets the high load need of offshore floating platform. Through the whole analysis, it proves the offshore platform proposed meets the demand of threewave environments, and it also proves certain theoretical basis for the platform optimization and control system design of such platforms.