Abstract: As the core production area of the mine gradually advances towards the deeper levels，the dynamic matching of the ventilation system with the deep mine air supply demand has become an urgent is⁃ sue to be addressed. Based on the Guyi mining area of the Fozi Mine in Guangxi，a 3D mine ventilation simulation was conducted using Ventsim to investigate and optimize the air-supply efficiency in deep mine workings，with the aim of improving long-distance ventilation performance in deep mining areas.The re⁃ search shows that for the improvement of the ventilation effect in the deep mine of the Guyi section，the short-term priority implementation plan one is to seal the 138 m middle section west wing return air shaft， set up the monkey car shaft local fan drainage and elevator shaft wind door，establish a coordinated mecha⁃ nism of shallow suppression and deep reinforcement，with a total return air volume increase of 7.99%，and an increase of 13.8% in the effective area. This quickly alleviates the problem of high resistance in the deep mine return air. In the medium term，combined with plan two，the 300 m middle section disorderly leakage points are sealed，and the dynamic balance of the 260 m middle section inclined shaft wind resis⁃ tance is achieved. The total air intake volume increases by 2.17%，and the leakage rate drops to 3%. In the long term，with plan three as the core，a fan is added in the 138 m middle section 9 line main roadway and a 401 m main fan is formed to form a relay boost，with a total air intake volume increase of 8.99%，an increase of 25.86% in the effective area，and a network efficiency increase of 1.39%. The deep mine venti⁃ lation efficiency optimization effect is remarkable. The research adopts a phased technical path，from shal⁃ low regulation，leakage control to relay air supply，step by step，providing a set of quantifiable and reus⁃able engineering practice solutions for the upgrade of the deep mine ventilation system of the mine.

Key words: mine ventilation system, deep mine ventilation, numerical simulation