Abstract: In view of the fact that a large number of surface cracks and fracture zones caused by coal mining subsidence in ecologically fragile areas have a significant impact on the content, distribution and movement of soil moisture in the mining area, and exacerbate the problems of soil and water loss and soil desertification, this paper takes the soil, aeolian sand, loess, clay and fly ash in the coal mining subsidence area and non subsidence area in Shendong mining area as the research object, through on-site sampling, in-situ monitoring The backfilling method of mining ground fissures in the study area is studied by combining indoor experiment and numerical simulation. After simulating the soil water movement of each reconstructed soil after backfilling the ground fissures according to the "three-step method", It is concluded that the soil water movement of the reconstructed soil with the selected backfill components uniformly mixed according to the mass ratio of 1:1:1:2 is the closest to the in-situ monitoring results of the soil in the non subsidence area, and the water retention performance of the deeper soil is slightly better than that of the undisturbed soil in the non subsidence area, which is the best backfill reconstructed soil.