Abstract: Diesel engines are widely used because of their high thermal efficiency and reasonable fuel economy. However, excessive particulate emissions (PM) of diesel engines have caused huge pollution to the environment. The diesel particulate filter (DPF) is the most efficient post-treatment device for reducing PM emissions. However, during the use of DPF, the increased soot loading or increased ash deposition after frequent regeneration might cause problems such as excessive exhaust back pressure. Therefore, reducing the DPF pressure drop and increasing the soot loading capacity under high ash ratio is important. In order to improve the DPF overall pressure drop characteristics and increase the soot loading capacity, this study proposed an irregular hexagonal channel diesel particulate filter (DPF) and established the mathematical model of DPF pressure drop. And the 3D computational models of irregular hexagonal channel DPF and quadrilateral channel DPF were built by AVL-Fire software. First, the DPF pressure-drop characteristic simulation test and bench test were carried out under different working conditions. The accuracy and effectiveness of the model were verified by comparing the experimental data. The diesel engine used in this study was a six-cylinder, turbocharged intercooled diesel engine equipped with a cordierite diesel particulate filter. The DPF used in the test had an outer diameter of 260 mm, a length of 270 mm, cells per single inch of 200, and a volume of 14.3 L. Then, different numerically analyzed tests were carried out to study the influence of exhaust flow rate, exhaust gas temperature, soot loading, and ash deposition on the pressure drop. At the same time, the results of the irregular hexagonal channel DPF were compared to those of quadrilateral channel DPF. The results showed that under different exhaust flow rate, the relative error between the simulated value and the experimental value was between 2.54% and 5.69%. The difference between the simulated value and the experimental value was small, and the change trend was consistent. The pressure drop of both channel structures increased with the increase of exhaust flow rate and exhaust gas temperature. Under the same exhaust flow rate and exhaust gas temperature conditions the irregular hexagonal channel DPF had lower pressure-drop value and smaller pressure drop rise rate, and the overall pressure-drop characteristics were better than the quadrilateral channel DPF. The irregular hexagonal channel structure DPF had a steeper soot filtration efficiency curve than quadrilateral channel during soot loading. The time taken for the soot filtration efficiency to reach 90% was shorter than that of the quadrilateral channel DPF. Different soot loading modes affected the DPF pressure-drop characteristics. The pressure drop of decreasing distribution was the highest, and the pressure drop of the incremental distribution was the lowest, the pressure drop of the uniform distribution was between the above two. Besides the irregular hexagonal channel DPF had a lower pressure drop in different distribution modes, which means it has a better soot loading mode adaptability. The ash deposited on inlet channel walls had a great influence on the pressure drop, and that deposited on the channel ends had less influence on the pressure drop. The irregular hexagonal channel DPF had a lower pressure drop curve under different ash distribution modes, which can effectively improve the soot and ash loading capacity. When the ash deposition was 10 g/L-1 and the ash distribution factor was 0, 0.5, 1, the maximum pressure drop of the irregular hexagonal channel structure DPF were all decreased. Under the regeneration pressure threshold the soot loading capacity increased by 36%, 59% and 100%. When the ash deposition gradually increased, the pressure drop of DPF of both structures increased linearly. In a word, the proposed irregular hexagonal channel structure DPF significantly reduced the DPF pressure drop and increased the soot loading capacity, thus improving the DPF working efficiency, reducing the regeneration frequency and prolonging the DPF service life.