Abstract: Pointed for combined stability on soil-steep slope and culvert for high roadbed engineering, the displacement and stability on culvert are insured firstly, and then the occurrence on reducing displacement is implemented. It is not consistent with fact for slope to reinforce singly. The engineering instance of a roadbed slope is analyzed with the numerical calculation(finite different method) to obtain contour charts for displacement and plastic state, which include no reinforcement, diaphragm walls and prestressed anchors-diaphragm walls, respectively. The results show the displacement is significantly reduced with combined reinforcement than single reinforcing method. Simultaneously, the culvert has not been influenced without linking plastic state, which has been compared with roadbed and the reinforcing cost is the lowest, So such is that the combined measurement can direct complicated roadbed engineering among theory, design and construction.