Gaoxin Avenue station of Line 3 of Chengdu Metro passes underneath Yiguanmiao overpass, therefore, the foundation piles of Yiguanmiao overpass have to be underpinned to facilitate the construction of the Metro station. In the paper, the challenges and key points in the design of Gaoxin Avenue station incorporating the underpinning of the foundation piles of Yiguanmiao overpass are analyzed, the scheme of "incorporating the underpinning structure with the retaining structure and the main structure of the Metro station and incorporating the active underpinning with the passive underpinning" is proposed under the principle of integrating the design of the Metro station with that of the underpinning structure. The execution of the proposed scheme shows that the safety of the opencut construction of the Metro station and the safety of the operating overpass can be guaranteed.