土壤水分是地球表层水循环、能量循环和生物地球化学循环中的重要组成部分，是研究喀斯特石漠化地区生态系统的关键参数。基于多时相的Sentinel-1 SAR数据与Alpha 近似模型构建土壤水分观测方程组，反演喀斯特石漠化地区地表土壤水分并对其时空变化特征及误差影响因素展开分析。研究发现观测周期内区域土壤水分总体变化趋势与降雨量变化趋势高度一致，石漠化地区土壤水分高值与空间异质性程度明显高于非石漠化地区。精度验证结果显示土壤水分反演结果的均方根误差为0.059 cm³/cm³，平均误差为0.026 cm³/cm³，该方法在区域地表土壤水分反演中表现出一定的适用性，分析认为地表土壤因周边的复杂生境条件产生的混合像元问题是导致反演误差的主要影响因素。研究可为利用短时间周期重复遥感观测方法获取复杂山区环境下的土壤水分提供参考，为喀斯特石漠化地区生态系统修复和生态产业发展提供支撑。

Soil moisture is the core component that links the earth's surface water cycle， energy cycle and biogeochemical cycle， and it is also the key parameter to study the ecosystem in karst rocky desertification area. The aim of this study was to retrieve the soil moisture with multi-temporal Sentinel-1 C-band SAR data and observation equations were constructed by using the Alpha approximation model over karst rocky desertification area. The spatial and temporal variation characteristics and the error influencing factors of the soil moisture retrieval results were analyzed. It is found that the overall change trend of soil moisture in the observation period is highly consistent with the trend of rainfall change. The maximum value of soil moisture and the degree of spatial heterogeneity in karst rocky desertification area is significantly higher than those in non-rocky desertification area. The results were validated using ground measurements of one acquisition date， with root mean squared error （RMSE） value of 0.059 cm³/cm³ and mean bias value of 0.026 cm³/cm³. The method of retrieval of soil moisture by Alpha approximate model is applicable to karst rocky desertification area， the mixed pixel problem caused by the surrounding complex habitat conditions of the surface soil is the main influencing factor of inversion error. These results can provide reference to obtaining soil moisture under mountain complex environment by multi-temporal observation method， and provide support for ecosystem restoration and ecological industry development in karst rocky desertification area.