Abstract: To clarify the adaptability and the mechanical performance of corrugated steel pipe (CSP) opencut tunnels in sloping terrain of high mountain area, a case study is conducted on a CSP opencut tunnel of the line J8 of the Alpine Ski Center in the Yanqing. The structural deformation and stress state during the construction and backfilling process are studied using field test and finite element numerical simulation methods. The results show the following: (1) The structure has an obvious unsymmetrical pressure due to the presence of the sloping terrain. The maximum deformation occurs at the north arch shoulder position behaving as a concave state of -1.00%, which meets the requirements of the specification (±2%). (2) The maximum stress appears at the valley of the plate at the north springline position in section 1（-320.16 MPa）, which is below the yield strength of Q345 steel plate. (3) The plate stress is composed of bending stress caused by bending moment and axial force stress caused by axial force. The former is more affected by the sloping terrain above the tunnel and the overall stress distribution characteristics of the tunnel are mainly controlled by the bending stress. (4) When there is no slope in the overburden soil above the tunnel, the structural deformation and stress distribution are both symmetrical between north and south. The five measuring points in the field test are at key points. However, the existence of the slope makes the deformation and stress state of the CSP opencut tunnel more complicated. Therefore, when monitoring is required, measuring points can be appropriately added to fully reflect the characteristics of the CSP opencut tunnel.