Soil saturated hydraulic conductivity (K_S) stands as the cornerstone index for assessing soil infiltration and permeability capabilities. Delving into its influencing factors is crucial for gaining a profound understanding and accurately evaluating the water conservation function transfer functions of forests. This study zeroes in on critical physicochemical indicators,including soil bulk density,organic carbon,field capacity,and porosity,within the natural secondary Betula platyphylla forest located in the eastern Qilian Mountains. By conducting a meticulous evaluation of the forestland's water-holding capacity and a thorough analysis of how soil physicochemical properties influence K_S,we aim to unravel the intricacies of this phenomenon. To achieve our objectives,we established a soil pedo-transfer function model utilizing the multiple stepwise regression analysis method. This model serves as a tool to predict and understand the variations in K_S based on soil properties. To validate the model's accuracy,we compared its predictive performance against six existing soil transfer function models,aiming to identify the optimal model tailored for our study area. Our findings are as follows: (1) The K_S values in this region span from 0.25 to 3.94 mm/min,averaging at 1.64 mm/min. Employing the entropy weight method to assess soil water-holding capacity underscores the significant weight carried by K_S. Notably,when the stand density falls within the range of 600 to 900 trees/hm²,the forestland demonstrates the highest comprehensive score for water-holding performance. (2) Pearson analysis further elucidates a negative correlation between K_S and clay,silt content,as well as soil bulk density. Conversely,K_S positively correlates with sand content,organic carbon content,and porosity. (3) In terms of predictive performance,the new model constructed in this study outperforms the other six soil transfer function models,with a coefficient of determination (R²) between predicted and measured values reaching an impressive 0.85. In summary,K_S emerges as a pivotal indicator for evaluating the water-holding capacity of natural Betula platyphylla forests in the eastern Qilian Mountains. Specifically,when the stand density is maintained between 600 and 900 trees/hm²,the forestland exhibits optimal water-holding performance. The newly formulated soil transfer function model in this study offers a reliable tool for estimating K_S in this region,providing invaluable data support and scientific rationale for the optimal management and ecological restoration of water conservation forests in the eastern Qilian Mountains. This research not only deepens our comprehension of soil water dynamics but also contributes significantly to the sustainable management and conservation of forest ecosystems,paving the way for more informed and effective conservation strategies.