To solve the problem that the blind heading distance was limited by the length of the air duct, taking Funiu Mountain extra-long highway tunnel as the engineering background, the structural parameters of the air bin were studied by numerical simulation. Taking the ventilation efficiency of the axial flow fan in the air bin as the evaluation standard, the optimization parameters of the air bin structure were obtained, and its overall ventilation effect was evaluated. The results show that the reasonable length-width ratio of the air bin is 1∶2; the spacing between two axial fans is 2-4 m. When the air demand difference between both ends of the air bin varies greatly, the air grab phenomenon in the air bin can be effectively reduced when the ratio of the middle diaphragm length to the air bin width is 1∶1.5. The "人" middle diaphragm with a radian of 30°effectively reduced the local loss by 59.40%. The air bin construction ventilation can effectively reduce the length of the air duct, remove the pollutants in the tunnel and achieve a good ventilation effect.