土壤水热动态直接影响区域水文过程，厘清土壤冻融过程中的水热动态变化是评估高寒地区水量平衡的关键。本文基于祁连山典型浅山区小流域气象和土壤水热的观测数据，利用 SHAW 模型模拟亚高山灌丛草甸土壤水热动态变化，分析土壤冻融过程中的水量平衡变化。结果表明：SHAW模型能较好地模拟亚高山灌丛草甸土壤温湿度随时间和垂直剖面变化规律，模型模拟的不同深度土壤温度同观测值的相关系数R≥0. 97，纳什效率系数NSE≥0. 88，均方根误差RMSE≤1. 89 ℃，土壤湿度模拟值同观测值的相关系数R≥0. 94，NSE≥0. 88，RMSE≤0. 05 m³·m^-3，总体上土壤温度的模拟效果比土壤湿度模拟效果更好，且土层越深模拟效果越好。根据土壤温度划定土壤冻融阶段发现亚高山灌丛草甸土壤冻融过程具有明显的单向冻结单向融化特征，其中完全冻结期持续时间最长，冻结发展期持续时间最短。土壤剖面的温度和水分变化趋势呈现"U"型，即在融化发展期和完全融化期的温度和水分较冻结发展期和完全冻结期更高，表层土壤水分波动较大，深层土壤水分则相对稳定。不同土壤冻融阶段的水量平衡特征差异明显，冻结发展期降水输入 4. 28 mm，水分支出以深层渗漏为主（9. 06 mm）；完全冻结期降水输入28. 69 mm，水分支出以地表径流为主（17. 90 mm）；融化发展期和完全融化期降水输入 106. 29 mm 和207. 31 mm，水分支出以蒸散发为主，其中植被蒸腾占78. 11%和71. 54%。土壤水分在冻结发展期和完全融化期呈现负均衡状态，而在完全冻结期和融化发展期，土壤水分呈现正均衡状态。研究结果为祁连山地区水资源形成和转化提供数据支持和理论依据。

Soil water-heat dynamics are pivotal in influencing regional hydrological processes. Understanding the dynamics of soil thermal and moisture changes during freezing and thawing processes is essential for assessing water balance in high-altitude regions. This study utilizes meteorological and soil water-heat observational data from a typical shallow mountainous catchment in the Qilian Mountains to simulate the water-heat dynamics of subalpine shrub meadow soil using the SHAW model，analyzing the changes in water balance during the soil freezing and thawing process. The results indicate that the SHAW model effectively simulates the temporal and vertical variations in soil temperature and moisture in subalpine shrub meadow soils. The findings demonstrates that the Nash-Sutcliffe Efficiency（NSE）for simulated soil temperature at various depths exceeded 0. 88，with ae correlation coefficient（R）greater than 0. 97and a Root Mean Square Error（RMSE）less than 1. 89 ℃. For soil moisture，the correlation coefficient（R）was greater than 0. 94，NSE was greater than 0. 88. and the RMSE was less than 0. 05 m³·m⁻³. Overall，the simulation of soil temperature is more accurate than that of soil moisture，especially in deeper soil layers. The soil freezing and thawing periods，delineated by temperature profiles， revealed a distinct unidirectional freezing and thawing characteristic of the subalpine shrub meadow soil，with the longest duration in the complete freezing period and the shortest in the freezing period. The trends in temperature and moisture across the soil profile exhibit a "U" shape，indicating higher soil temperatures and moisture during the thawing period compared to the freezing period，with significant fluctuations in surface soil moisture and relative stability at deeper layers. The water balance characteristics are significantly varied across different soil freezing and thawing periods. During the freezing period，the precipitation input is 4. 28 mm，with the main expenditure of water is deep percolation at 9. 06 mm. In the complete freezing period，the precipitation input is 28. 69 mm，with the main expenditure of water is surface runoff at 17. 90 mm. During the thawing period and the complete thawing period，the precipitation input is 106. 29 mm and 207. 31 mm respectively，with the major water output through evapotranspiration，where plant transpiration accounted for 78. 11% and 71. 54% respectively. The soil moisture shows a negative balance during the freezing and complete thawing periods，indicating a net loss of moisture. Conversely，the soil moisture exhibits a positive balance during the complete freezing and thawing periods，signifying a net increase in moisture. This study may provide empirical data and theoretical support for the formation and transformation of water resources in the Qilian Mountain region.