Located in the fill of Hechuan Station Yard on SuiYu Railway Line, the doublearch opencut extralargespan tunnel for Hechuan Station is a largespan highfilled highwayrailway separate grade opencut tunnel. The tunnel has a total length of 71.5m, truncated portals, 17.32m inner net clearance width of single span, 45.2m maximum width of the doublearch structure and 9m filling depth on the top of the crown. This paper introduces the design of the main structure of this opencut tunnel.