Abstract: According to the line and construction characteristics of Shanxi Central Yellow River Diversion project, TBM construction was adopted when crossing the black-tea mountain nature reserve. After the ventilation tunnel was cancelled due to the actual project condition, TBM has a blind heading range of 26km, so the ventilation issue had become an important factor that restricted the project safety, progress and economic benefit. On the basis of using existing tunnel and ventilation equipment, a kind of composite ventilation system that included pressure mode, suction mode, tandem mode and roadway mode was put forward. In this new mode, the layout and operation of ventilation system were divided into three stages. Check calculation results of air pressure and wind pressure proved that it could satisfy the ventilation requirement. In addition, a kind of non-destructive relay fan connection piece was introduced into this project, which can reduce the air leakage at relay fan and provide a better protection for long-distance ventilation.