利用自动气象站观测降水、ERA5再分析资料和NCEP GDAS资料，基于水汽收支分析、HYSPLIT后向轨迹追踪和水汽输送贡献率等方法对2024年7月22-24日甘肃省东南部一次特大暴雨的水汽输送特征进行分析并定量讨论其水汽来源及贡献率。结果表明：此次暴雨区位于高空急流出口区，其气流辐散增强低层水汽的垂直输送，使湿层变得深厚；台风“派比安”与副热带高压等持续协同影响，将南海和孟加拉湾上空的水汽输送到暴雨区，提供充足水汽，暴雨区维持显著近地面湿区和高可降水量。水汽收支和追踪分析结果显示，水汽流入主要发生在 800~500 hPa 的南边界，流入量最大为 1237 kg·m-1·s-1。暴雨发生前，水汽主要源于南海和孟加拉湾上空，其水汽通道分别占所有轨迹数量的48%和42%，水汽输送贡献率分别为51. 45%和43. 31%。暴雨发生时，水汽主要源于南海上空，其水汽通道占所有轨迹数量的 53%，水汽输送贡献率为 57. 98%。此外，西太平洋和西北通道的水汽输送对本次暴雨也有一定的贡献。这将有助于理解中国西北内陆地区特大暴雨的形成机制，为未来甘肃地区的特大暴雨预报提供一定参考。

Based on automatic weather station observations of precipitation，ERA5 reanalysis data and NCEP GDAS data，through methods such as water vapor budget analysis，HYSPLIT backward trajectory tracking and water vapor transport contribution rate，this paper analyzed the water vapor transport characteristics of a severe rainstorm event that occurred in the southeastern part of Gansu Province from July 22 to 24，2024，and quantitatively discussed its water vapor source and contribution rate. The results showed that the rainstorm area was located in the exit zone of the upper-level jet stream，where the airflow divergence enhanced the vertical transport of low-level water vapor，causing the moist layer deeper. The continuous synergic influence of Typhoon " Prapiroon" and the subtropical high transported water vapor over the South China Sea and the Bay of Bengal to the rain‐ storm area，providing sufficient water vapor，and the rainstorm area maintained a significant near-surface wet area and high precipitable water. The results of water vapor budget and tracking analysis showed that the inflow of water vapor mainly occurred at the southern boundary of 800~500 hPa，with a maximum inflow of 1237 kg·m-·1 s-1. Before the rainstorm，the water vapor mainly originated from the South China Sea and the Bay of Bengal，and the water vapor channels accounted for 48% and 42% of all tracks respectively，and the water vapor transport contribution rate was 51. 45% and 43. 31% respectively. When the rainstorm occurred，water vapor mainly originated from the South China Sea，its water vapor channels accounted for 53% of all the tracks，and the contribution rate of water vapor transport was 57. 98%. In addition，the water vapor transport in the Western Pacific and Northwest Passage also contributed to the rainstorm. This would be conducive to understanding the formation mechanism of the extraordinary rainstorm in Northwest China，and provided certain references for the future forecast of extraordinary rainstorm in Gansu Province.