Abstract: Aiming at the high risk of gas accumulation in the face of high gas mines and the insufficient efficiency of traditional ventilation technology, this paper proposes a controlled circulation ventilation system based on inert gas.The system dynamically regulates the oxygen and gas concentration in the roadway by introducing nitrogen as an inert medium and combining an air curtain barrier device with a gas extraction system.The specific method includes: closing the air door of the bypass lane, utilizing a nitrogen generator to generate nitrogen to form an air curtain to block oxygen infiltration, and discharging the high-concentration gas mixture through the gas extraction pipe; setting up a circulating purification zone to eliminate the low-concentration gas, and real-time monitoring of the gas concentration in order to adjust the supply of nitrogen and the amount of gas extraction.Through CFD numerical simulation, it is verified that the gas curtain can significantly inhibit the spread of gas, reduce the gas concentration in the rear area to the safety threshold(<5%),and at the same time optimize the flow rate and pressure distribution in the roadway to avoid the accumulation of gas.The results show that the system can effectively solve the ventilation problems of high-gas mines, combining the advantages of air increase and temperature reduction, energy saving and dynamic control, and providing a technical guarantee for safe and efficient production in mines.