Abstract: With the downward movement of the production center of Wangershan Gold Mine，there are some problems in the deep mine，such as long ventilation route，large resistance，lagging ventilation engineering，insufficient ventilation and bad environment. It is necessary to optimize the mine ventilation system to create a good working environment for underground workers.By adopting the partition ventilation mode，a relatively independent ventilation system is formed above the level of -550 m and below the level of -550 m. The deep ventilation project is reformed，and the return air shaft is newly excavated. An axial flow fan is added to the return air side at the level of -550 m as a return air auxiliary fan to adjust and con⁃ trol the air volume in the deep middle section. The Ventsim software is used to solve the network of the opti⁃ mized ventilation system. According to the calculation results，the total air volume of the optimized Wang⁃ ershan Gold Mine can reach 170.4 m3 /s，of which the return air volume of the mining area below -550 m is 111.6 m3 /s，which can meet the air volume required for deep mining and improve the underground working environment.

Key words: deep mines, ventilation system optimization, zoning ventilation