Abstract: Based on the Mohr-Coulomb failure criteria, the yield functions were deduced under the passive earth pressure condition. By using of the in-situ test data and assisted by FLAC2D, the numerical analysis of an unstable soil slope located at the No.205 national highway was carried out. The results show that the increment of elastic area and the decrement of lateral displacement in the soil slope after cement-grouting are notable, also the strain-sheared area and the volume strain area tend to dissipation.