Abstract: Taking the coalmine dump slopes as the objects, this paper analyzes the effects of slope aspect, slope position and restoration year on the stability of soil aggregates on coalmine dump slopes using Le Bissonnais (LB) method, and studies the damage mechanism of soil aggregates. The results show that, under the three treatments (fast wetting, slow wetting and stirring after prewetting) of LB method, the soil particle size on the dump slopes is mainly in agglomerations >2 mm. The stability of soil aggregates gradually increases from the upper to the lower slope and is better on a shady than on a sunny slope: with an increasing restoration years, these trends are more significant. According to the relative gelatinization index and the relative mechanical crushing index, the clay expansion mechanism has little damage to the soil aggregates, while dissipation and mechanical force are the main mechanisms of the soil aggregates. Therefore, it is necessary to reduce the damage of soil aggregates by external forces such as rainstorms and tillage to improve the stability of the soil structure and promote ecological restoration of coalmine slopes.