Abstract: The newly-built Huayingshan tunnel on the Nanchong-Dazhu-Liangping expressway is 8168m long with its entrance and exit passing through coal strata. Because it is a gas-rich tunnel, construction ventilation is a key component of the construction engineering. In this paper, based on current mechanical ventilation modes and the characteristics of the Huayingshan Tunnel, a combination mode of forced ventilation and jet flow gallery ventilation is adopted. By calculating the amount of fresh air required for tunnel ventilation, dividing the work area in light of gas concentration, and calculating the specific resistances of the ventilation ducts and tunnel, the optimal configuration for the construction ventilation fans is carried out, and the construction ventilation scheme for each work area is determined.