Abstract: The engineering technology method of stratified covering and rolling is adopted in the soil of mine reclamation area, and the degree of soil compaction is obviously higher than that of ordinary soil, which is not conducive to the growth of plants. Laboratory experiments and comparative analysis were used to simulate three horizontal soil samples with compacted densities of 1.35 g/cm³, 1.65 g/cm³ and 1.95 g/cm³.Arbuscular mycorrhizal fungi were selected to study the promoting effect and mechanism of mycorrhizal fungi on plant growth in soil with different compaction densities.The results show that, by the Glomus mosseae mycorrhizal inoculation, the affinity degree between mycorrhizal and plants is high, the length of hyphae is increased significantly, the activity space and scope of plant roots are expanded and the resistance and growth condition of plant are improved, the ability and growth of plants to absorb N, P, K and other nutrients from the soil are improved, so that the suitable growth degree of plants in the soil density level of 1.65 g/cm³ is improved to the same as that of 1.35 g/cm³.