Abstract: Surface displacement is monitored during the construction process of Taizhou-Jinyun highway S9 loose high slope in Zhejiang Province. The elastic modulus and internal friction angle of rock are back-calculated by elastoplastic displacement back analysis with surface displacement of slope, including horizontal and vertical displacement, which are employed to predict the surface displacement from the next excavation of slope. As the surface measuring points are set after the excavation of the slope, the measured displacement is incremental displacement resulting from the excavation of lower slope. Therefore, the method of incremental displacement back analysis is used. The calculated results of cases show that the predicted horizontal displacement at the same measuring point set in the upper slope agrees with the measured value, and that the predicted vertical value has relatively large errors compared with the measured one.