构建合理的生态环境脆弱性评价体系是生态环境脆弱性评价的关键。为了提高生态承载力和生态环境质量，促进生态系统良性发展，基于Landsat 5/9卫星遥感影像、数字高程模型、土壤、气象及社会经济数据，利用CRITIC客观赋权法开展生态环境脆弱性评价，使用转移矩阵及障碍度模型，探讨了2000—2022年天水市生态环境脆弱性变化及其成因。结果表明：裸土指数、土地利用类型、气温和降水量是影响天水市生态环境脆弱性的主要因子；天水市生态环境脆弱性呈北高南低分布；相比于2000年，2022年天水市生态脆弱性整体降低，除武山、甘谷中北部部分区域极度脆弱区保持不变以外，总体上天水市大部分极度脆弱区降为重度或中度脆弱区，但城区周边部分区域受城市化影响由中度脆弱区升高为重度或极度脆弱区；2022年天水市极度脆弱区脆弱性降低的主要影响因素为裸土指数、土地利用类型和降水量。未来一段时间内因地制宜植树种草、提高人工影响天气能力和灌溉水平，是降低天水市生态环境脆弱性的主要手段。

Establishing a reasonable assessment system for ecological environment vulnerability is very important to the high-quality development of ecological environments. This work collects Landsat 5/9 image， topography， soil， meteorological and socioeconomic data to assess ecological vulnerability by the CRITIC objective weighting method， then investigates spatiotemporal changes and its influence factors using transition matrix method and obstacle degree model in Tianshui city with a key position in water source conservation， soil and water conservation， and ecological security barriers. The result shows that the ecological vulnerability in Tianshui city presented a pattern of high in the north and low in the south， and generally decreased during 2000-2022. Except for Wushan and north-central part of Gangu with no change of extremely vulnerable areas， most area in Tianshui city had been transformed from extremely vulnerable areas to severely or moderately vulnerable areas. However， some areas surrounding the urban districts had been changed from moderately vulnerable areas to severely or extremely vulnerable areas due to urbanization. In 2022， bare soil， land use types， and precipitation are dominated factors for decreasing of extremely vulnerable areas. In order to effectively reduce the areas of extremely vulnerable areas in Tianshui city， the capabilities of planting tree and grass， artificial weather modification， and irrigation capacity should be improved continuously in line with the local conditions in future.