Visual analysis illustrated the steady and rotating cavitation in a centrifugal pump at different flow rates. The cavity structures under different NPSH were captured and the cavity lengths, including the supercavity length were obtained. The corresponding vibrations of the volute and bearing were measured by using acceleration sensors. The influences of the cavity structures on the vibrations were analyzed. Experimental results showed that the vibration was increased when the cavitation occurred at the pressure side, especially when the supercavitation occurred. The cavitation at the suction side was usually thin and its influence on the vibration was relatively small. The growth rate of the cavity length at the pressure side was increased after the appearance of supercavitation. At the flow rates of 0.6Qd and 0.8Qd, the vibration turned from increase to decrease soon after the rotating cavitation appeared, and the ratios of the cavitation number to attack angle at the turning point were close to each other. And then the vibration was increased again when the stable cavitation occurred at the pressure side, and finally it was decreased sharply when the pump head was extremely small. Besides, the vibration was increased when large shedding cavities blocked the flow channel. During the rotating cavitation, the cavity structures in the opposite channels were similar to each other, and the cloud shedding frequency was around 27 Hz according to visual observations and the fast Fourier transform of inlet pressure fluctuations.