In ecologically fragile arid and semi-arid mining regions, open-pit mining has created extensive spoil dumps characterized by extreme soil moisture and temperature regimes, constituting the primary challenge for vegetation restoration and ecological rehabilitation. To address this challenge, there is an urgent need to explore novel rehabilitation approaches that reconcile energy development with ecological conservation. This study investigated retaining wall on open-pit coal mine spoil dump, utilized an integrated approach of field monitoring and numerical simulation to elucidate the regulatory effects and mechanisms of retaining wall on soil moisture and temperature distribution. The results indicated that the retaining wall significantly improved the water retention and temperature regulation ability on the leeward side. The influence of the retaining wall on the leeward side was concentrated in the range of 1-1.5 m, and the depth of influence was mainly concentrated in the surface layer and 10 cm soil layer. In the surface soil layer, the soil moisture on the leeward side (average 23.93%) increased by 2.66% compared to the windward side (average 21.27%), and the variation range of soil temperature on the leeward side (21.0-26.5 degrees C) was less than that on the windward side (19.5-25.4 degrees C). Furthermore, the soil water dissipation rate on the leeward side (linear fit slope: -0.10) was 33.3% lower than that on the windward side (linear fit slope: -0.15). Numerical simulations further elucidated that by altering local airflow patterns, retaining wall facilitated the formation of a windless zone extending over 3 m horizontally on the leeward side under wind speeds of 4 m & centerdot;s-1, thereby mitigating evaporation and temperature fluctuations. This study elucidates the ecological regulation potential of retaining walls beyond traditional mechanical functions, providing new theoretical support and technical approaches for low-cost ecological restoration of open-pit coal mine waste dumps in arid and semi-arid regions.