Abstract: The high-yield and high-efficiency intensive production mode in western mining areas is an important direction of the national energy strategy, and high-efficiency mining in large-scale mining space working faces is the core path to realize this mode. However, the large-scale coal gangue discharge and strong strata pressure behaviors caused by mining in large-scale mining spaces are becoming increasingly severe, seriously restricting the coordinated development of ecological environment protection and safe and efficient resource development in mining areas. Backfill mining is an important approach to consume gangue and control mining pressure. However, existing backfill methods are difficult to meet the requirements of high-efficiency mining and rapid consumption of gangue in large-scale mining space working faces in terms of production efficiency, solid waste disposal capacity, and backfill height. To address this, a large-scale mining space gangue non-compacted backfill method for western mining areas is proposed. Its technical connotation is elaborated, the key challenges of large-scale mining space backfill mining working faces are analyzed, namely the complex evolution of overburden structure under low compaction rate in large-scale mining spaces and the difficulty in controlling strong strata pressure in non-compacted backfill working faces, and a large-scale mining space gangue non-compacted backfill technology system is established. Key scientific issues are discussed, including the evolution mechanism of mechanical characteristics and long-term bearing performance of the non-compacted backfill body, the spatio-temporal evolution law of overburden structure in large-scale mining space non-compacted backfill mining, and the roof control mechanism based on the cooperative bearing of non-compacted backfill body–support–surrounding rock. Key technical issues are analyzed, such as high-efficiency preparation and large-flow transportation technology of backfill materials, development of hydraulic supports for large-scale mining space gangue non-compacted backfill, high-efficiency mining-backfilling integration process in large-scale mining spaces, strong strata pressure control in large-scale mining space mining, and comprehensive monitoring of non-compacted backfill effects in large-scale mining spaces. This method innovates a collaborative mode of efficient coal production and large-scale disposal of gangue, improves the backfill mining technology system for large-scale mines, and has broad application prospects in large-scale disposal of gangue, improvement in mining and backfilling efficiency, and strong strata pressure regulation in stopes.