In order to solve the difficulties in ground performance test of new full-scale gearbox vibration isolation device, such as large size, heavy weight and many test states, and to shorten test period and reduce test cost, a test method for evaluating the vibration isolation performance of the gearbox vibration isolation device by measuring the transfer rate of dynamic load was presented. Details about the scheme, test fixture installation, test content and process of the ground performance test were brought forward. The theoretical analysis and the comparison test results of traditional vibration level verified the feasibility of the measured load transfer rate test scheme and the reliability of the test results, which provided a new test method for the following similar system level full-scale vibration isolation performance test. The experimental results showed that the vibration isolation efficiency of the new type of gearbox vibration isolation device for X,Y,Z three directions achieved over 80%, and achieved the expected vibration reduction effect.