The invention discloses a coal mine ventilation system. The coal mine ventilation system comprises a main air return channel and multi-air-inlet and multi-air-return equipment, wherein the multi-air-inlet and multi-air-return equipment is communicated with the main air return channel and formed by a plurality of auxiliary air return channels. The main air return channel is formed in the top of a coal mine main roadway and connected with a blowdown stack, the auxiliary air return channels are formed in the tops of branch roadways on the two sides of a coal mine coal face, draught fans are arranged at the joints of the auxiliary air return channels and the main air return channel, and suction fans are arranged at air inlets of the auxiliary air return channels. According to the coal mine ventilation system, the ventilation distance of the coal face is shortened, the content of fresh air in the coal face is greatly increased, air quality in the roadways is similar to air quality outside a mine, and therefore it is avoided that good health of workers is damaged and various potential safety hazards are caused due to poor ventilation, and the accident rate of the coal mine is effectively controlled.