Abstract: For the failure mechanism and weakness of the existing scour protection measures for offshore wind power foundation, the standing vortex principle of disturbance flow ring is used to reduce the subsidence and destruction of the riprap layer by water flow, the riprap layer fixed with a sleeve is applied to weaken its edge destruction and a mat of biomimetic water grass, which has a function of hindering the diving flow and the lateral flow, is used to weaken the shear failure of the riprap layer. These three new types of riprap composite protection methods, i.e. ‘the riprap + disturbance flow ring’, ‘the riprap + sleeve’ and ‘the riprap + mat of biomimetic water grass’, are proposed respectively, and based on the arrangement of the three new measures, 10 specific composite protection designs are proposed. And then, physical model tests are carried out and the protection effects of different composite protection methods are assessed. The results show that under the action of ocean currents the protection effects of the three composite protection methods are all better than that of riprap protection alone, with a protection efficiency being above 66%. When the laying range of riprap is 3 times the single pile diameter, the thickness of riprap is 2 times the median particle diameter of riprap, the inner diameter of the disturbance flow ring is set up to 2 times the single pile diameter and the distance away from the riprap layer is 0.5 times the pile diameter, the disturbance flow ring can play a better role, so that the water flow reaching the riprap layer and the surrounding sediments can be dispersed and the flow velocity can be slowed down. Such a composite protection method can be reached to 82.2% in protection efficiency and can achieve the ideal protection effect.