Abstract: The concept of three-dimensional ecological mine construction in coal mining treats surface ecological environment protection and underground coal resource extraction as an integrated three-dimensional whole. By applying systems theory, the various factors influencing the surface ecological environment, together with the impacts potentially induced by mining activities, are analyzed in an integrated manner, enabling unified consideration and the determination of ecological protection thresholds. On this basis, underground mining modes are planned in accordance with surface ecological protection requirements, so that mining-induced disturbances are controlled within recoverable and reconstructable ranges, thereby realizing full-process ecological protection and environmental reconstruction during coal resource extraction and achieving coordinated development between underground energy exploitation and surface ecological environment protection. Meanwhile, considering the dual attributes of coal gangue in three-dimensional ecological mine construction—as both a solid waste generated during coal mining and a recyclable resource for ecological mine development—this study proposes and establishes two filling mining technology systems: gangue-disposal-oriented filling and target-controlled filling. Gangue-disposal-oriented filling aims primarily at gangue treatment, uses goafs as disposal spaces, and takes filling efficiency and filling capacity as key objectives, emphasizing parallel operations to increase filling speed and reduce costs; through multiple disposal pathways such as regional joint gangue management and in-situ disposal without hoisting or surface handling, it realizes underground gangue consumption and significantly reduces surface stockpiling pressure and subsequent remediation intensity, demonstrating feasibility and sustainability for large-scale application. Target-controlled filling focuses on surface ecological environment protection and, in combination with ecological disturbance thresholds under designed operating conditions, establishes a feedback loop of monitoring, criteria, and adjustment to ensure that maximum subsidence, surface tilt, horizontal deformation, curvature, and aquiclude integrity remain within prescribed limits, thereby achieving defined ecological protection objectives. On this basis, a filling mining technology system integrating goaf resource utilization with ecological protection threshold control is established, and the mechanisms and implementation routes of gangue-disposal-oriented filling and target-controlled filling are clarified. Long-term engineering practice demonstrates that the construction of a three-dimensional ecological mine supported by the source reduction and filling mining of coal gangue can achieve the dual goals of on-site disposal of solid waste and protection of key ecological elements under complex geological and multiple ecological constraints.