Abstract: To understand the pipeline leakage characteristics of the large-scale main gas drainage system in coal mines and the multi-physical fields of the gas flow in pipeline, a three-dimensional numerical model is developed based on Ansys CFX and the process of gas drainage pipeline leakage is investigated.The influence of different leakage positions, different leakage intensities, and different negative pressures of the pumping station on the gas flow in the gas drainage pipeline is studied.The results show that the leakage intensity and the negative pressure are the important factors affecting the internal gas flow field in the gas drainage pipeline, and the leakage occurring near the pumping station of main gas drainage system is prone to be captured easily.The results of this paper are expected to provide technical support for the safety prevention and control of pipeline leakage accidents in the main gas drainage system and also suggestions for the optimization of the allocation of safety prevention and control resources.