Natural disasters such as landslides often occur in Qinghai under the double deterioration ofearthquake and freeze-thaw cycles, ecological slope protection is an effective way to preventand control this type of disaster. In this paper, the mechanical properties of root-soilcomposites are investigated experimentally using triaxial apparatus and dynamic single shear(DSS) apparatus, and based on the discrete element method, a contact model more suitablefor reinforced soil materials is proposed to study the dynamic properties of root-soilcomposites under cyclic shear from a fine viewpoint. Based on the results of the study, thefollowing conclusions were drawn: 1) The presence of roots under the action of freeze-thawcycles increases the strength properties of the soil. At the same number of freeze-thaw cycles,the shear strength and cyclic resistance of the root-soil composites are higher than those of theloess. And the strength of the root-soil composites decreases with the increase of the numberof freeze-thaw cycles and then flattens out; 2) The proposed contact model can bettersimulate the softening effect of reinforced loess material under cyclic shear, which is moresuitable for simulating the mechanical behavior of loess and laying the foundation for furtherstudy of reinforced loess material from a fine viewpoint.; 3) The presence of the root systemwill improve the stability of the slope soil, and the root system will have a positive effect on theshear strength of the soil when the moisture content is within a certain range. The presence ofthe root system also increases the cyclic resistance of the soil. Under the same cyclic shearstress conditions, the number of damage cycles of the root-soil composites is higher than thatof the loess, the cumulative shear strain is less than that of the loess. However, the root systemno longer exerts positive effects under saturated conditions. The research results can providesome guidance for the construction of ecological slopes in loess areas, and provide a new wayto investigate the dynamic properties of root-soil composites from a fine viewpoint.