The refinement of high-frequency structural-borne noise of powertrain mounting system is the main issue of the noise， vibration and harshness （NHV） development and research for electric vehicles. Moreover， the available upper frequency limit of the elastomer test system for mount dynamics is increased substantially to 3 kHz due to the innovation of test equipment. The experimental researches focusing on high-frequency dynamics is carried out for a rubber mount of electric vehicle. Firstly， the boundary conditions of mount dynamics test are analyzed. It is pointed out that the rubber stiffness and bracket modals of mount， and the test fixture modals are three influences for dynamics. Secondly， the main characteristics of mount dynamics are studied. the correspondence between the peak of dynamics and the influences is identified by mass schemes. Then， The effects of three influences on dynamics are concluded， and the principles for designing and optimizing of mount and its brackets for electric vehicle are proposed. The interior noise of final drive order is refined by stiffness schemes and mass schemes， which can indicate the necessity of researches and the correctness of conclusions about rubber mount high-frequency dynamics.