Resonant knocking sensor

The invention relates to a resonant knocking sensor. The resonant knocking sensor comprises a housing, a bearing seat and a vibration piece, wherein the inside of the housing is provided with a bearing surface; the bearing seat is provided with a base part, a support part which extends outside from a top surface of the base part, and a vibration disk which is connected with one end of the support part, the bearing seat is fixedly arranged inside the housing, and a bottom surface of the base part is arranged on the bearing surface of the housing; and the vibration piece is arranged on the vibration disk of the bearing seat. According to the resonant knocking sensor, sensor of different sensing frequencies can be assembled through the same housing and vibration piece simply by changing the geometrical size of the support part of the vibration disc, namely, the resonant knocking sensor can change the resonant frequency in a low-cost mode to be applied to items of different knocking frequencies to be detected.