The pore scale model considers the porous structure and can fundamentally elucidate the filtration dynamics inside the DPF. In this paper, a developed two-dimensional pore scale model based on lattice Boltzmann method is adopted. A new determination method for soot particle threshold value is proposed. Flow field characteristics along different streamlines are analyzed. Particle cluster distributions and their effects are analyzed. The results show for streamlines close to the porous wall, the inlet contraction pressure drop and the outlet channel pressure drop account for a higher proportion and dominate the total pressure drop. It is necessary to focus on reducing the resistance along the last 1/5 of total outlet channel length. Near the particle deposition area, inlet channel pressures increase and outlet channel pressures decrease, creating a low-pressure area. Soot particles tend to deposit in the middle part of the channel when considering the effect of particle dynamic deposition.