In order to study the potential slip surface damage form, displacement characteristics and stability effects of slopes under different angle α between vegetation root system and slope freeze-thaw interface. The results show that with the increase of thawing depth, the equivalent plastic strain penetration zone of plain soil and root-soil composite slopes during spring thawing period is more obvious and prone to plane slip along the freeze-thaw interface. Compared with plain soil slopes, the maximum displacement of root-soil composite slopes during spring thawing period (March) is reduced by about 69.65%, and the maximum displacement of root-soil composite slopes during spring thawing period (April) is reduced by about 71.88%. The maximum displacement of the root-soil composite slope is reduced by about 69.65% in the spring thawing period (March) and 71.88% in the spring thawing period (April), and the reduction of the displacement of the root-soil composite slope tends to increase with the increase of α angle, which shows that the root system has strong soil consolidation ability when it reaches the freeze-thaw interface. When the angle α between the root system and the freeze-thaw interface is increased from 45° to 90°, the root-soil composite slope is more susceptible to planar sliding along the freeze-thaw interface. When the angle between the root system and the freeze-thaw interface is increased from 45° to 90°, the safety coefficient of the slope of root-soil complex tends to increase, and when the root system is perpendicular to the freeze-thaw interface of the slope, the root system has a relatively maximum effect of enhancing the soil consolidation and slope protection of the slope during the spring-thaw period, which can effectively improve the stability of the slope during the spring-thaw period. The research results have theoretical research value and practical guidance significance for the discussion of plant roots at the freeze-thaw interface on the stability of spring thaw slopes.