To solve the problems of low efficiency and poor uniformity in polishing blisk, a rotary-assisted horizontal vibration mass finishing process was adopted. Based on the discrete element method (DEM), the behavior of particles in the process was simulated to study the characteristics of the particle behavior on the blisk, and the variation law and the distribution of the particle acting force. The results show that the particles have different movement feature in the flow passage area and the non-work-piece area, and the particles on both sides, where there is no workpiece, can only act on the two sides of the blisk. During the rotating process of the blisk, the blade would experience some sudden forces when entering or exiting the particle flow field. The force on blade surface increases at first and then decreases along the rotating direction. Moreover, changing the rotating direction affects the fluctuation range of the forces acting on the back surface and the basin surface of blade. The effect of particle on the blade surface is obviously different, whose RSD
value is between 0.3 and 0.6, and the strong force of the back surface of blade mainly appears in the areas of inlet and tip while at the basin surface of blade is generally focused in the areas of exhaust and tip.