植被碳汇是露天煤矿生态环境评价的重要指标，精确反演植被碳汇并进行准确分级对探索矿区生态修复至关重要。为此，提出一种基于粒子群优化算法的露天煤矿植被碳汇分级方法。基于Landsat遥感影像和气象数据，采用光能利用率模型，反演出内蒙古胜利一号露天煤矿区2005—2020年间排土场的植被碳汇时空分布；通过构建目标函数并迭代计算，获取了该区植被理想光能利用率、最佳气温和降水条件，量化并建立了植被碳汇分级标准；对不同时期各个排土场的植被碳汇结果进行分级，并对分级面积和占比的时空变化进行分析。结果表明：(1) 2005—2020年间研究区植被固碳能力呈上升趋势，年均增长值和增长率分别为1.43 gC/(m²·a)和6.97%。(2) 各排土场生态修复后，植被碳汇值大幅提高，极高和高植被碳汇区面积不断扩大。(3) 排土场生态修复效果存在差异，南北排土场表现最佳，沿帮次之，内排土场相对较差。到2020年南、北排土场极高植被碳汇区面积分别达0.94和0.92 km²，占比为92%和94%；沿帮排土场极高和高植被碳汇区面积达3.64 km²，占比66%；内排土场极高植被碳汇区面积增长至1.22 km²，占比达31%；2020年南、北和沿帮排土场已不存在极低植被碳汇区。研究成果不仅为露天煤矿生态环境评估提供了重要的数据支持，也为矿区生态修复策略制定提供了科学依据。

Vegetation carbon sink serves as a crucial indicator for the ecological assessment of an open-pit coal mine. The accurate inversion and grading of vegetation carbon sink play a significant role in exploring the ecological restoration of coal mines. This study proposed a method for grading vegetation carbon sink of an open-pit coal mine based on the particle swarm optimization (PSO) algorithm. Specifically, using a light use efficiency (LUE) model, this study first determined the spatio-temporal distributions of the 2005‒2020 vegetation carbon sink in the waste dumps of the Shengli No.1 open-pit coal mine through inversion based on Landsat images and meteorological data. Then, by developing objective functions and conducting iterative computation, this study ascertained the ideal LUE and optimal temperature and precipitation conditions in the coal mine, followed by the quantification and development of criteria for vegetation carbon sink grading. Finally, this study graded the vegetation carbon sink results of the waste dumps during various periods and analyzed the spatial-temporal changes in the areas of varying grades and their proportions. The key findings are as follows: (1) From 2005 to 2020, the carbon sequestration capacity of vegetation in the study area showed an upward trend, with average annual growth and growth rate of 1.43 gC/(m²·a) and 6.97%, respectively; (2) After ecological restoration of waste dumps in the coal mine, the vegetation carbon sink values increased significantly, and zones with extremely high and high carbon sink values gradually expanded; (3) The ecological restoration effects differed across various waste dumps in the coal mine, proved to be the best in southern and northern waste dumps, followed by the marginal waste dump on the margin, with the inner waste dumps exhibiting the poorest ecological restoration effects. By 2020, in southern and northern waste dumps, zones with extremely high carbon sink values covered areas of 0.94 km² and 0.92 km², respectively, accounting for 92% and 94% of the total areas of the dumps, respectively. In the marginal waste dump, zones with extremely high and high carbon sink values occupied an area of 3.64 km², representing 66% of the total area of the waste dump. In the inner waste dump, the area of zones with extremely high carbon sink values increased by 1.22 km², accounting for up to 31% of the total area. In 2020, there was no zone with extremely low carbon sink values anymore in the southern, northern, and marginal waste dumps. This study will provide both critical data for the ecological assessment of the open-pit coal mine and a scientific basis for developing ecological restoration strategies for the mining area.