According to the deformation characteristic of the high liquid limit soil embankment of the expressway, a numerical mechanics model for analyzing the deformation of embankment was established, in which the elastoplasticity of foundation and the cooperation deformation of road surface and roadbed were comprehensively taken into account, then the finite element calculation program was made out for analyzing the deformation of high liquid limit soil embankment. The deformation of some embankment was calculated by use of this program, and the calculated horizontal displacement and vertical depression of the embankment were equivalent to the measured ones. It indicates that the results calculated by finite element method can used to dynamically guide the construction of high liquid limit soil embankment.