Abstract: Abstract: By changing the inlet edge blade shape of the plane to get different degrees of the back swept blade, simulating the back swept degree of 40°, 65°and 90° of axial flow pump blades and original prototype blades pump of the three-dimensional solid-liquid two-phase flow channel to get the characteristic curves and distributions of solid particles within the impeller. Characteristic curves show that the back swept angle will reduce the efficiency and head of the pump, which means the reduction grows with the growth angle. With the increase of the particle diameter, the particle moves backward to the pressure surface, therefore the solid phase volume fraction increases, meanwhile the solid phase volume fraction at the suction surface near the hub of the inlet side also increases; with the increase of particle volume fraction, the solid phase volume fraction at the pressure surface reduces and the solid phase volume fraction at the suction surface of the blade increases. It is predictable that the solid phase moves according to the angle between the radial direction and the solid phase velocity direction. The smaller the angle is the more obvious the radical flow is and the bigger the backswept angle is, then the solid phase is more difficult to contact with the blade suction surface than the pressure surface. When the sweep angle is small, the degree of radial flow is the major factor affecting the distribution of the solid phase on the pressure surface of the blade, otherwise when the sweep angle is large, the sweep angle would be the major factor, the greater the sweep angle, the smaller volume fraction of the solid phase on the pressure surface of the blade. Because the 90°sweep angle is large enough, and the radial flow at the suction surface is the smallest, when the back swept angle is 90°the solid phase volume fraction is small and uniform at the suction surface and the pressure surface near the rim of the blade, severe local wear can be avoided. When the swept angle is 40°and 65°, the solid phase volume fraction on the pressure surface near the rim of the blade is large. So it will easily lead to severe wear. In order to verify the correctness of the simulated results, the 65° back swept blade model is compared with the back swept blade of the sludge axial flow pump in the Nanjing Jiangxin island sewage treatment plant, meanwhile the swept angle of the blade is also close to 65°. The actual operating condition of the back swept impeller is complex, and the particle concentration and diameter may not be uniform, but according to the 2.3 and 2.4 sections, the impact of the particle concentration and diameter on the distribution of the solid phase on the blade is small, the solid volume fraction is just changing in on the original position with the particle diameter and the concentration changes. So the wear leaf diagram of the back swept blade can be comprised with the solid phase distribution of the simulation results.Based on the above, increase the back swept angel can reduce the solid volume on the pressure surface of the blade and the 90° back swept angle condition is better than that of 40° and 65° according to the solid volume.