The invention relates to a variable-main-scale swinging plate type wave energy power generation device model testing method and belongs to the wave energy power generation technology field. According to requirements of water-power tests on different swinging plate angles, swinging plate damping, the swinging plate position, different mooring stiffness matrixes, different mooring modes, different model main scales and different model structures in a model test, a physical flow and a test operation flow of a test system are proposed, and a detailed operation method is provided for key model condition change operation. The method is advantaged in that problems of relatively too-many variables and condition combination complexity existing in a semi-submersible swinging plate wave energy power generation platform model test are solved, each type of test conditions can be completely covered, test operators can be facilitated to effectively and orderly accomplish the test, the test operators are facilitated to acquire accurate and reliable test data, test efficiency is improved, the test time is saved, and test cost is reduced.