To effectively and economically determining the dimension of inclined shaft crosssection and ventilation pipe of a doubletube tunnel, a case study is conducted on a long inclined shaft in the Xingshandong tunnel of the YichangXingxian connection line. Comparison is conducted on the energy consumption of fans with ventilation pipes under various diameters and corresponding civil work cost of inclined shaft crosssection. The results show that increasing the height of inclined shaft crosssection appropriately, optimizing the layout space of the inclined shaft ventilation pipes, and increasing the diameter of the ventilation pipes can improve the tunnel construction ventilation effect and reduce the overall construction cost of the tunnel.