Abstract: The wet multiple disc brakes (WMDB) are progressively replacing the traditional dry brakes in agricultural machinery. Considering the WMDB operating characteristics, the paper discusses the causes of the WMDB vibration and noise, points out the main influence factors of the WMDB noise, and then derives the formulation which can be used in the WMDB vibration. Some measures to reduce noise are proposed. The theoretical analysis was verified to be correct by the test results.