Working life of the middle trough is an important indicator of the scraper conveyor. Improving the wear resistance of the middle trough can effectively prolong the service life. Based on the nonsmooth wear-resistant theory, the bionic optimization of the middle trough was carried out by designing the pits on the surface of the middle plate. The orthogonal test design of L9 (34) four factors and three levels was used. The structural static analysis and frictional contact analysis of the original middle trough sample and nine groups of the bionic middle trough samples were carried out respectively, and the simulation results were compared. Results showed that the pits had stress slow-release effect, torque effect, edge strengthening effect, and the function of collecting wear debris. So the pits could reduce fatigue wear, abrasive wear, impact wear, adhesive wear, thermal fatigue, and thermal wear on the middle trough. Then, the influence of pits' parameters on the wear resistance of the nonsmooth surface was studied by the contact analysis of the rectangular blocks. Results showed that the surface of the pit was easily deformed to produce more compressive and bending strain energy. The pits had the effect of releasing stress thus improving the wear resistance of the nonsmooth surface. At the same time, with the increase of the length and spacing of the pits, the wear resistance of the nonsmooth surface increased first and then decreased. There was an optimal value as the length of the pit was 2 mm and spacing was 9 mm. With the increase of the pit depth, the wear resistance of the nonsmooth surface increased gradually.
