Abstract: A multi-stage centrifugal pump mainly used for oil extraction, which incls two essential components, namely, a rotational impeller comprising several blades and a stationary diffuser. The shapes of blades and flow passages are designed by using three-dimensional flow theory. The configuration is characterized by the impeller length and the diffuser length being almost equal, with the moving blade being provided with an extension at the trailing edge, smaller wrap angle of the stationary diffuser blade, shorter single-stage and smaller outside diameter, and so forth.