Diesel particulate filter (DPF) is one of the most effective devices to solve automobile exhaust emission problem. A DPF model with multilayer porous media (PM) and varied porosity is proposed to improve regeneration performance and conversion rate. Effects of PM setting, inlet temperature and flow rate on pressure distribution, thermal performance and conversion rate of the DPF are investigated. The results indicate that the static pressure of DPF with multilayer PMs is increased with the improvement of temperature under the condition of porosity P = 0.4, and the static pressure of the incremental model with multilayer PMs is 22.3 Pa and 42.5 Pa lower than that of the holistic and degressive filter, respectively. The pressure distribution is more uniform and the conversion rate is higher than P = 0.5 and P = 0.6. In addition, the increase of porosity is conductive to the rapid heating and reducing the static pressure. Furthermore, the conversion rate of multilayer (P = 0.3 + 0.4+0.5) is increased by 59.24% within t = 400 s and heat transfer performance is significantly improved when the mass flow rate increases from mf = 10 g/s to mf = 30 g/s. Hence, the incremental PM setting is contribute to the achievement of high conversion rate and better thermal performance, reducing engine emissions.