In the process of heap leaching, the free particles in the heap leaching system move with the flow of the solution, which affect the speed and efficiency of the leaching. For small grain size particles, although it is difficult to clog the interparticle pores, its large amount of adhesion on the pore wall surface also affect the infiltration of solution into the pore wall and thus affect the leaching efficiency. In this experiment, the effects of particle size, particle density and fluid velocity on the migration and adhesion behavior of fine particles in pores were investigated by means of simulation. The simulation results show that when the particle size is 1×10-6 m, almost no particles deposite in the pores. With the increase of particle size, the number of particles attached to the surface of the pore wall first increase and then decrease. The particle adhesion percentage of different density is more than 90% at the peak. The main adhesion sites of particles are the outer walls of curved pores and the small pores with low flow velocity and low slope. The analysis shows that the larger the particle size and density, the greater the influence of gravity and inertia on its trajectory, while the smaller the influence of fluid on its trajectory, the easier it is to get close to the pore wall during migration, resulting in particle attachment. In addition, the large particle size and high density particles mainly migrate in the large pores, and the trajectories are relatively concentrated. However, when small particle size and low density particles migrate in high flow velocity fluid, their horizontal motion amplitude is larger, the migration trajectory distribution is more dispersed, and the distribution is also in small pores.