Abstract: In the frozen soil areas of highway construction, due to the presence of freezing and thawing, the mechanical properties of soil of the slopes of the roadbeds change easily in the periodic freezing and thawing. In this background, this paper selects typical slopes of the roadbeds of the Qinghai-Tibet region under different conditions as the target of study, carries out comparative study of the shear strain of the slope by FLAC^3D finite difference method. The results showed that shear strain in frozen soil varies very little under freezing conditions, and the slopes of the roadbed is stable. However, when the soil ablation reaches its maximum, the weak belt is formed in freezing and thawing interface with large water content, the shear strain varies a lot and the slopes of the roadbed is unstable. The soil cohesion, internal friction angle, unit weight reduction under the condition of freezing and thawing lead the decrease of shear strength of slope, resulting in large shear strain of roadbed slope. The results provide important references for prevention and control of similar situation of slope of the roadbed in permafrost areas.