A dynamic model was established based on Newtonian mechanics theory and analysis was made on vibrating characteristics in time and frequency domain to the modes of constant flow and pressure. Measurement mechanism was designed to test the vibration of stator of JB32H-type radial piston pump. It is concluded from analysis and test results that the acceleration of stator vibrates periodically in time domain on the two modes. The amplitude on the mode of constant pressure is smaller than the one on the mode of constant flow. The frequency band is wider on the mode of constant flow than that on the mode of constant pressure. Stator vibrates in the range of higher frequency on the mode of constant flow than on the mode of constant pressure. Constant pressure system of pump is in the function of low-pass filter.