Abstract: To improve the life-span of mud pump piston, natural biological surface morphology was imitated to design and process the dimple-shaped bionic units on the existing mud pump piston surface. The wear-lives of bionic piston and standard piston of BW-160 type mud pump were compared and studied under the same bench test conditions. The results show that the dimple-shaped bionic mud pump piston is able to obviously increase the life-span. For the BW-160 type piston, the bionic unit can improve the piston life to 2.19 times than the original life. Dimple-shaped structure parameters on the surface of piston have a significant impact on the life-span of piston. The impacts of dimple diameter, center angle and depth on piston life are reduced in sequence. The dimple diameter should not be too large or too small; the life-span of piston is increased with the reduction of dimple center angle; when dimple depth is larger, the piston life will become longer. Through analyzing the wear mechanism of bionic piston, it is found that the existence of dimple-shaped biomimetic unit can change the piston stress situation, increase the lubricant storage space, improve the interface lubrication condition, reduce the frictional resistance of friction pair, accommodate partial wear debris, and avoid the re-scratching of friction pair. Field drilling test was carried out on experimental results. For F1300 type piston,the life-span of dimple-shaped bionic piston was increased by 93% than standard piston.