草原湖泊水位变化预示着草原生态环境的变化，是草原生态变化的重要指标。利用2018年11月—2022年1月ICESat-2卫星的ATL13全球内陆水体数据，构建呼伦湖高精度水位变化序列。使用DAHITI、Hydroweb和G-REALM水位数据进行结果验证。依据湖泊面积与水位变化关系，构建水位面积关系模型，分析湖泊水位季节性变化特征及外界因素对湖泊水位的影响。研究结果表明：2018年11月—2022年1月，呼伦湖水位整体呈现上升趋势，年均水位上涨率为0.49 m·a^-1；湖泊每年3—6月水位下降，7—10月水位上涨，11月—次年2月水位稳定。通过与DAHITI、Hydroweb和G-REALM水位数据对比验证可知，ICESat-2卫星监测水位数据稳定，水位序列精度高，均方根误差为9.7 cm，结果可靠。ICESat-2卫星水位监测成果结合湖泊水位面积模型，可实现多时段、高精度湖泊水位监测，并计算水位季节性变化时间序列，结果显示，呼伦湖水位季节性特征明显，且年际变化趋势基本稳定，春季至夏季水位下降，夏季至冬季水位上升。湖泊水位变化受外界因素的影响较大，气温升高引起的蒸发量增大是湖泊水位下降的主导因素，气温、蒸发量与水位变化呈现出较强的负相关性；人工注水对湖泊水量的补给使湖泊水位上升，且在2021年注水期内水位上涨趋势明显。

The water level changes of grassland lakes indicate the changes of grassland ecological environment, which is an important indicator of grassland ecological changes. We use the ATL13 global inland water data of ICESat-2 satellite from November 2018 to January 2022 to construct a high-precision water level change sequence of Hulun Lake. The results are verified using DAHITI, Hydroweb, and G-REALM water level data. Based on the relationship between lake area and water level change, a water level area relationship model is constructed to analyze the seasonal characteristics of lake water level changes and the influence of external factors on lake water level. The research results showed that: from November 2018 to January 2022, the water level of Hulun Lake showed an overall upward trend, with an average annual water level rise rate of 0.49 m·a^-1. The water level of the lake decreases from March to June each year, rises from July to October, and stabilizes from November to February of the following year. It is known from the comparison and verification with DAHITI, Hydroweb, and G-REALM water level data that the ICESat-2 satellite monitoring water level data is stable, the water level sequence precision is high, and the root mean square error is 9.7 cm, which is reliable. The Combination of the ICESat-2 satellite water level monitoring results and the lake water level area model can achieve multi-time and high-precision lake water level monitoring, and calculate the time series of water level seasonal changes, which showed that the seasonal characteristics of Hulun Lake water level are obvious, and the inter annual trend is basically stable. The water level decreases from spring to summer and rises from summer to winter. The changes of lake water level is greatly affected by external factors. The increase of evaporation caused by the rise of temperature is the main factor leading to the decrease of lake water level. The temperature, evaporation, and water level change showed a strong negative correlation. The recharge of the lake water volume by artificial water injection has increased the lake level and the trend of increasing water level is obvious during the injection period in 2021.