Abstract: More and more attention has been focused on the study of construction technology of highway tunnel considering environmental protection with the developing of national income and social advancement. Based on the actual conditions of Lao-shan highway tunnel in Nanjing, a shed-tunnel structure which is an environmental protection structure for the outlet of tunnel adjacent to mountain, is suggested. The stability of this new structure has been studied by means of FEM simulation with reduction of the soil strength. The following conclusions can be drawn from the computation results of the most dangerous zone: combining anchor-shotcrete with shed-tunnel structure, a reasonable complete supporting system of the slope was formed, and the whole slope with shed-tunnel structure is safe too. The structure which is adopted according to the natural topography, such as shed-tunnel or half-tunnel, should be adopted to protect the natural environment and slope in the complicated zone, for example, the slope adjacent to mountain.