<p>Centrifugal pumps are extensively employed in ocean engineering, such as ship power systems, water transportation, and mineral exploitation. Pressure fluctuation suppression is essential for the operation stability and service life of the centrifugal pump. In this paper, a new method of bionic structure is proposed for the blade surface of a centrifugal pump, which is inspired by the fish scale and comprises a leading edge, a trailing edge, and two symmetrical side edges. This fish scale structure is applied to the blade pressure and suction surfaces, and an impeller with a fish scale structure is constructed. A test rig for a centrifugal pump is developed to determine the pressure fluctuation in the pump with a prototype impeller and fish scale structure impeller. Results reveal that the dominant frequency of pressure fluctuation in volute is the blade passing frequency (<i>f</i>_bpf) of 193.33 Hz, which is triggered by the interaction between the tongue and the impeller. The bionic structure of the fish scale effectively suppresses the pressure fluctuation amplitude at <i>f</i>_bpf. From flow rates of 0.6 <i>Q</i>_<i>d</i> to 1.2 <i>Q</i>_<i>d</i>, the average suppressions in pressure fluctuation amplitudes at <i>f</i>_bpf are 20.98%, 5.85%, 19.20%, and 25.77%.</p>