[Objective] The ecology of open-pit coal mine areas is fragile and water resources are scarce. Therefore, the use of microorganisms for mine reclamation has become a research hotspot with regard to ecological reconstruction of mining areas. The effects of soil inoculation with arbuscular mycorrhizal fungi (AMF) on maize root growth and water use charateristics under the conditions of a reconstructed soil sponge ecological structure in an open-pit mine dump were determined in order to provide a scientific basis for the implementation of ecological agriculture in mining areas.[Methods] A soil column simulation experiment was conducted in a laboratory. Three treatments were evaluated:a bare soil column (CK), maize without bacterial inoculation (NM), and maize with bacterial inoculation (AM). The stable hydrogen and oxygen isotope tracer technique was used to study water use characteristics by maize roots.[Results] ① The AMF treatment increased maize root growth and changed maize root distribution. Total root length, total root surface area, total root volume, and number of root tips for the AM treatment were 19.3 %, 14.8 %, 9.1 %, and 34.0 %, respectively, higher than observed for the NM treatment. The proportions of fine roots smaller than 0.3 mm and coarse roots larger than 0.7 mm for the AM treatment were 3.2 % and 3.5 %, respectively, higher than for the NM group. ② AMF changed water use characteristics by maize roots by depth. The proportion of water used by maize for the AM treatment from the 0-20 cm soil layer was 5.5 % higher than for the NM treatment. ③ The moisture content of the 0-20 cm soil layer of the AM treatment was significantly lower than for the NM treatment. The moisture content of saturated clay layer of the CK treatment was higher than for the NM treatment, which was higher than for the AM treatment. AMF improved the ability of maize roots to absorb water, and affected the release of water in the clay layer.[Conclusion] AMF inoculation of a reconstructed soil sponge structure in an open-pit mine dump can promote maize root development, improve maize water utilization strategy, and make full use of the water stored in the water layer in the sponge structure.