In order to study the influence of fluid mixed with solid particles in mechanical seal chamber on the erosion of sealing chamber wall and bellows under complex working conditions,based on CFD theory and method,k-ε turbulence model and discrete DPM model were used to simulate the solid and liquid mixing flow field,and the pressure field distribu- tion on the surface of the sealing cavity and the outer surface of the bellows was obtained. The erosion area distribution of the inner wall of the seal chamber and the outer surface of the bellows under the action of solid particles under different working conditions was studied,the trajectory of solid particles in the flow field and the change of the escape amount and movement state of solid particles in the flow field during mechanical seal operation were analyzed. The results show that the particles are mainly affected by particle resistance,floating gravity,pressure gradient force and surface reaction force of bel- lows and sealing chambers. In the rotating flow field,the particles move forward spirally in the same direction as the rota- ting direction. In the case of no rotating speed,the erosion mostly occurs on the outer surface of bellows near the entrance, and in the rotating flow field,the erosion mostly occurs on the wall near the back of the sealing chamber. The particle es- cape rate is decreased with the increasing of rotating speed. This research provides theoretical basis for the design and lay- out of mechanical seal cavity and the optimization of mechanical seal device.