河套灌区水盐平衡是水资源研究的热点问题，通过研究河套灌区地下水位的时空变异状况，可以为灌区水资源的科学管理和可持续发展提供一定的科学依据。 本研究以内蒙古河套灌区作为研究区，用传统统计学、地统计学和经验正交函数方法对永济灌域、义长灌域和河套灌区1990～2015年地下水埋深的时空变异特征和影响因素进行了分析，主要得出如下结论： （1）在永济灌域、义长灌域和河套灌区三个空间尺度，从1990～2015年潜水位分别下降近0.7m、0.4m和0.4 m，平均下降速率为2.8 cm/a、1.6 cm/a和1.7 cm/a，平均变异系数分别为24%、29%和31%，随着空间面积的增大，变异系数呈增大的趋势。永济灌域、义长灌域和河套灌区空间插值结果表明，不同时期地下水埋深的空间分布存在一定的差异性，但总体上以1.5～2.5 m范围为主，平均占比分别为61%、60%和49%。 （2）永济灌域26年的最优变异函数有高斯、指数和球状模型，变程多在300 m～6 km；义长灌域26年的最优变异函数以高斯模型为主，变程多在5～7 km；河套灌区26年的最优变异函数有指数和球状模型，其中以指数模型为主，区域变程多在6～20 km，随着三个区域空间面积的增大，变程逐渐增大，说明地下水埋深的空间相关性逐渐增强。永济灌域月地下水埋深变化可以分为三种分布类型，义长灌域可以分为两种分布类型，河套灌区月地下水埋深变化可以分为五种分布类型。三个区域都存在全区埋深变化深和全区埋深变化浅这两种空间分布类型，对应月份分别为2001年到2010年的1到4月份和2001年到2010年的11月份，但是三个区域相同分布类型的高值区和低值区存在一定的差异性。 （3）潜在蒸散发和灌溉入渗补给量是永济灌域年地下水埋深的主要驱动因素，义长灌域蒸发量和灌溉入渗补给量是年地下水埋深的主要驱动因素。通过分析永济灌域和义长灌域月地下水埋深的影响因素，发现降雨量、潜在蒸散发（蒸发量）以及引水量会共同影响月地下水埋深的变化，但是在不同月份中，降雨量、潜在蒸散发（蒸发量）以及引水量中的单个因素会起主导作用。土壤质地（砂土、粉砂土和黏土）与河套灌区和义长灌域月地下水埋深的相关性比较显著，但与永济灌域的相关性不大，说明土壤质地对河套灌域和义长灌域地下水埋深的影响比较大。

The water-salt balance in Hetao Irrigation District is a hot issue in water resources research. By studying the temporal and spatial variation of groundwater level in Hetao Irrigation District, it can provide a scientific basis for the scientific management and sustainable development of irrigation water resources. In this study, Hetao irrigation district of Inner Mongolia was used as the research area, and the spatial and temporal variability and the influencing factors of depth to groundwater table in the Yongji Irrigation Sub-district, Yichang Irrigation Sub-district and Hetao Irrigation District from 1990 year to 2015 year were studied by traditional statistics, geostatistics and empirical orthogonal function method. The main results are as follows: (1) At the three spatial scales of Yongji Irrigation Sub-district, Yichang Irrigation Sub-district and Hetao Irrigation District, the three regions of the phreatic level has decreased by nearly 0.7m, 0.4m and 0.4m from 1990 year to 2015 year, respectively, and the average rate of decline is 2.8 cm/a, 1.6cm/ a and 1.7 cm/a. The average coefficient of variation of the three regions is 24%, 29% and 31%, respectively. As the spatial area increased, the coefficient of variation shows an increasing trend. The spatial interpolation results of Yongji Irrigation Sub-district, Yichang Irrigation Sub-district and Hetao Irrigation District indicate that there are some differences in the spatial distribution of depth to groundwater table in different periods, but the overall range is 1.5~2.5 m, with an average proportion of 61%. 60% and 49%. (2) The optimal variogram of Yongji Irrigation Sub-district for 26 years is Gaussian, exponential and spheroidal models with a range of 5 to 7 km, and the optimal variogram of 26 years in Yichang Irrigation Sub-district is dominated by Gaussian model with a range of 5 to 7 km, and the 26-year optimal variogram of Hetao Irrigation District has exponential and spheroidal models, of which the exponential model is dominant, and the range is more than 6~20 km. As the spatial area of the three regions increases, the range increases gradually, indicating that the spatial correlation of depth to groundwater table is gradually enhanced. According to the empirical orthogonal function analysis of the monthly depth to groundwater table in Yongji Irrigation Sub-district, Yichang Irrigation Sub-district and Hetao Irrigation District, the variation of monthly depth to groundwater table in Yongji Irrigation Sub-district can be divided into three types, and can be can be divided into two types in Yichang Irrigation Sub-district, and can be divided into five types in Hetao Irrigation District. The three regions all have two spatial distribution types of the depth to groundwater table of the whole area changes deeply and the depth to groundwater table of the whole area changes shallowly, and the corresponding months mainly are 1 to 4 months from 2001 year to 2010 year and 11 month from 2001 year to 2010 year, respectively, but there are some differences between the high value area and the low value area of the same distribution type in the three regions. (3) Potential evapotranspiration and irrigation infiltration recharge are the main driving factors for depth to groundwater table in Yongji Irrigation Sub-district, and evaporation and irrigation infiltration recharge in Yichang Irrigation Sub-district are the main driving factors for depth to groundwater table. By analyzing the influencing factors of the depth to groundwater table in the Yongji Irrigation Sub-district and Yichang Irrigation Sub-district, it is found that rainfall, potential evapotranspiration (evaporation) and irrigation will together affect the change of monthly depth to groundwater table, but in different months, single factors in rainfall, potential evapotranspiration (evaporation) and irrigation will play a leading role. The effect of soil texture on Hetao Irrigation District and Yichang Irrigation Sub-district is relatively large, but the impact on Yongji Irrigation Sub-district is relatively small, indicating that the soil texture has a great influence on depth to groundwater table of Hetao Irrigation District and Yichang Irrigation Sub-district.