Centrifugal pump plays an important role in dealing with the water flooding accident in a coal mine. However, it has disadvantages of high mechanical loss and low energy utilization efficiency. Thus, studying the drag reduction performance of a centrifugal pump is essential. Not only it can save energy, but also can improve the pump stability. Here the drag reduction of the centrifugal pump is realized by arranging bionic microstructures on the centrifugal pump blade surfaces, and the optimal design parameters are obtained. In the paper, the influence rules and mechanisms of the bionic microstructures on the drag reduction of the pump are investigated by simulation method, and the variations in the impeller working torques caused by the bionic microstructures, compared to that of the pump with smooth blade surfaces, are used to characterize the drag reduction ratio. The effects of the arrangement, shape, and height size of the bionic microstructures are considered. And the microstructures are arranged on the outlet of the blade suction surfaces with an area ratio of 13%. Results show that in the three arrangements of vertical rib, vertical groove, and parallel groove, the parallel groove has the highest drag reduction ratio. And for all the flow rates analyzed, all the parallel grooves with different cross-section shapes can realize drag reduction. In the three shapes of triangle, semicircle, and rectangle, the rectangular shape has the best drag reduction performance. The drag reduction ratio does not change monotonically with the microstructure height increasing. For the three heights analyzed, all the three kinds of microstructures with h=0.5 mm have the largest drag reduction ratio. For all bionic micro-structured surfaces, their drag reduction ratios increase with the flow rate increasing. For all conditions, the blade surface with a parallel rectangular groove has the highest drag reduction percentage of 8.39%. The bionic microstructures arranged on the blade surface will inevitably influence the flowing behaviors, especially for the near-surface fluid layer. The flow resistances are mainly caused by the frictional resistance and the differential pressure resistance. The friction resistance is composed of the viscous shear stress and the turbulent Reynolds stress, which are closely related to the flowing behaviors. In the paper, the path line figure near the blade surface, as well as the nephogram of velocity, turbulence kinetic energy, and shear stress are used to analyze the influence rules and mechanisms. The low-speed fluid layer trapped in the microstructures can effectively control and weaken the turbulence of the near-surface fluid layer, thus reducing the turbulent kinetic energy loss. Meanwhile, there are obvious reverse flow vortices in the microgrooves as shown in the path line figure. The reverse flow vortex can work as a "rolling bearing", which transforms the sliding friction into the rolling friction, thus reducing the fluid friction resistance. The low-speed fluid layer trapped in the microstructures can also increase the effective thickness of the boundary viscous layer and decrease the velocity gradient of the near-surface layer, resulting in lower surface frictional resistance. This research provides theoretical guidance for reducing energy loss of the centrifugal pump by using the bionic microstructure surface.