Abstract: The test model of finite plate stiffened by blocking mass used to attenuate the structural vibration is established. The vibration frequencies, the modal shapes of finite plates affected by blocking mass and its capacity to attenuate the plate vibration are measured. The test results are compared with the theoretical calculations. The attenuation trend of the vibration transmission from the exciting plate to the receiving plate is concluded for plates with three different sizes. The results show that the insertion loss resulting from test and calculation have little difference. There are "block-frequency-range" and "pass-frequency-range" of vibration transmission, their comprehensive effects result to effectively attenuate vibration transmission of finite plate and the attenuation effect gets better with the increasing of the mass radio.