为探究离心水泵的空化特性以及变化规律，以离心泵空化试验平台为基础，实测不同空化程度下水泵振动信号。进而引入平滑伪Wigner-Ville分布时频分析技术，利用SPWVD变换获得各工况下振动频域特征，实现了对离心泵空化特征研究。试验表明：在额定工况下NPSH值为10.920 m，该状态下没有空化现象发生，而随着NPSH值逐渐减小，离心泵发生空化现象，在空化数为5.643 m时空化现象最明显，频率稳定在190 Hz附近。此外，随着空化程度逐渐增强，致振频率呈逐渐减小再增加的趋势，但始终稳定在160~200 Hz范围内。

In order to explore the cavitation characteristics and change rules of centrifugal pump，the vibration signals of centrifugal pump under different cavitation degree are measured based on the cavitation test platform of centrifugal pump. Furthermore，the time-frequency analysis technology of smoothed pseudo Wigner-Ville Distribution is introduced，and the frequency-domain characteristics of vibration under various working conditions are obtained by using SPWVD transformation，the cavitation characteristics of centrifugal pump are studied. The test results show that the NPSH value is 10.920 m under rated conditions，and there is no cavitation phenomenon under this condition. However，with the NPSH value decreasing gradually，the cavitation phenomenon occurs in the centrifugal pump. The cavitation phenomenon is most obvious when the cavitation number is 5.643，and the frequency is stable near 190 Hz. In addition，with the increase in cavitation degree，the vibration frequency is decreasing and increasing，but it is stable in the range of 160 to 200 Hz.