Abstract: Biofilm is a common bacterial community in porous media,which can interact with suspended particles and affect the migration and deposition of particles.The Lattice Boltzmann-discrete element coupling method (LBM-DEM) was used to study the migration of suspended particles in porous media covered with biofilm.The presence of biofilms reduced the pore-throat size and the DLVO repulsive barrier,which helped enhance the deposition of suspended particles.The pressure difference between inlet and outlet was the main factor affecting the retention rate of particles.Under low-pressure difference between inlet and outlet,particles couldn't break through the exclusion barrier,and the flow force of high-pressure difference could increase the permeability by changing the deposition position of the particles.The change of ion concentration in the solution mainly affected the exclusion barrier.In the solution with high ion concentration,the particle retention rate had little response to the change of pressure difference.In the solution with low ion concentration,the particle retention was greatly affected by the inlet and outlet pressure difference.In addition,the effects of inflow velocity on the adhesion and rolling of suspended particles were also observed from a mesoscopic perspective.The angle between the initial deposition points of particles and the incoming flow direction decreased with the increase of particle velocity.