〗Deep ice core drilling is an important constituent part of the polar scientific research. In polar exploration sampling process, at the same time of achieving high quality samples, the drilling fluid pollution to the polar region should be reduced to the lowest degree, which has great significance to the polar native environment protection. According to the stratum conditions of the polar scientific drilling, a transport model of pollutant in the snow layer is established by Visual Modflow. When the pollutants concentration maintains constant, numerical simulation for the borehole pollutants is made to predict the pollutants in snow plume diffusion range in a decade. On this basis, contrastive analysis is made on the pollutant dispersion ability of snow under different dispersion coefficient. The drilling fluid used in the polar is 10 times that of water, with the increase of pollutants viscosity, the diffusion range will also be reduced correspondingly. This study result lays the important theoretical and technical basis for the evaluation of the influence of drilling fluid used in polar ice core drilling on the polar environment.