The structural optimization design of 6-DOF marine active wave compensation hydraulic platform was made to improve the bearing capacity and space compensation capacity of the hydraulic platform and reduce the volume and weight of the compensation platform. The marine wave compensation parameters index of hydraulic platform with 6-DOF was given according to the wave running form.Using virtual prototype technology, the parameterized model of the platform was establish in ADAMS simulation software. With its maximum load as the optimization goal, the structure size of the parameterized model was optimized, the optimization results of the platform structure size was acquired. The results show that after optimization, the load capacity of the 6-DOF marine wave compensation hydraulic platform increases by about 15% compared with the initial, and the stroke of the leg hydraulic cylinder decreases by about 13%. The platform load capacity is improved and the structure is more compact and reasonable. In order to test the effectiveness of the optimization of the structure size of the platform, SolidWorks software was used for modeling, and ADAMS software was used to simulate and test the compensation ability of the model.