The working mode of constant-pressure radial piston pump includes the mode of constant flow and constant pressure. The dynamic model of stator vibration was established and the analysis was made on the stator vibrating velocity in frequency domain to the two modes. Measurement mechanism was designed to test the vibration of stator of JB32H-type radial piston pump. It is concluded from the analysis and test results that the velocity of stator vibrates periodically on the two modes. Stator velocity vibrates in the range of higher frequency on the mode of constant flow than on the mode of constant pressure. The conclusions are helpful to the noise control of piston pump.