The retaining structures including the balance weight retaining wall were set up outside the new embankment unilaterally in mountain region highway embankment widening reconstruction. The finite element software phase2 was used to build a detailed numerical model for describing the interaction between soil and wall, which introduced the joint element. Based on two-step approach, the nonzero displacement constraints were imposed on metope to simulate translational and rotational (RBT) active extraversion deflection of the retaining wall. The effect of the different deformation amount of active extraversion deflection in the retaining wall on the embankment differential settlement was analyzed. The results were verified and compared with the test results of geotechnical centrifuge model. It shows that the rigid retaining wall is interacted and interdependent well with the new and old embankment. Additional differential settlement, which is caused by the active extraversion deflection of retaining wall, is 51% to 67 % of total differential settlement when the ratio of the extraversion value to wall height is 1% to 3 %.