Because of the adsorption of pollution particles by DC electric field, the pollution of DC arrester is more serious than that of AC arrester. The UHV DC polar bus arrester also has three parallel resistor columns inside the insulation jacket, so the change of the surface electric field of the insulating jacket and the radial electric field between the resistor columns and the insulating jacket will have a certain impact on the operation of the arrester. In this paper, according to the characteristics of pollution distribution in DC field, the electric field simulation model of UHV DC polar bus arrester under pollution is established. The electric field on the surface of umbrella skirt and the radial electric field between resistor columns and insulating jacket are calculated and analyzed when the overall pollution is not uniform and the local drying zone occurs. The results show that overall pollution will lead to the increase of the surface electric field of insulating jacket and internal radial electric field, but the smaller value will not cause corona and flashover. However, the appearance of local drying zone will result in excessive surface and redial field strength on the surface of umbrella skirt and the air gap between resistor columns and insulating jacket, which will endanger the safe and stable operation if the arrester.