Abstract: Large-scale coal mining in alpine mining regions has caused severe degradation of surface vegetation, permafrost layers and water resources, while ecological restoration efforts face critical shortages of natural soil materials. Utilizing coal gangue solid waste from mining areas as the primary substrate material for reconstructed coal gangue matrices with biochar amendments to optimize hydraulic properties is of great significance for water conservation and vegetation recovery in alpine mining regions. In this study, we investigated the effects of biochar addition at four levels (0%, 1%, 2%, and 3% by mass) on the moisture dynamics of coal gangue-based reconstructed soil through controlled soil column infiltration and evaporation experiments. The results demonstrated that cumulative infiltration and wetting front migration depth exhibited significant power-function relationships with time under all biochar treatments. With the increase of biochar addition, the cumulative infiltration increased first and then decreased, and the cumulative infiltration of 2% treatment was the highest. Both the time when the wetting front reached the bottom and cumulative evaporation decreased progressively with higher biochar content, and the evaporation dynamics were well described by the Rose model. After evaporation, the soil moisture content of each treatment was shown as 2%>1%>3%>0%, with the treatment groups retaining 47%, 55%, and 25% higher average water content, respectively, compared to the control. These findings indicate that the reconstructed soil with 2% biochar addition has good infiltration and evaporation performance. The results can provide theoretical basis and technical support for the soil reconstruction research with coal gangue-based soil reconstruction in alpine mining area.