Abstract: Based on the automatic observation station data of Lijiang Airport, NCEP reanalysis data, and the HYSPLIT trajectory model, the characteristics of heavy rainfall at Lijiang Airport from 2007 to 2019 were analyzed.The results show that the number of heavy rainfall days at Lijiang Airport varies greatly between years, with an annual average of 7.8 days and a maximum daily precipitation of 92.3 mm.The heavy rainfall weather patterns exhibit obvious seasonal variation characteristics.The number of heavy rainfall days from June to September, namely the rainy season, accounts for 90% of the total, and the rainstorms mainly occur in July and August.According to the main impact systems of 500 hPa, seven kinds of heavy rainfall weather situations are summarized at Lijiang Airport.Among the seven types, the shear cold front and two high convergence zone are the most dominating weather patterns of heavy rainfall, accounting for 40%.During the period of heavy rainfall, the whole layer over Lijiang Airport is featured with large vertical velocity.The water vapor mainly comes from the height of 700 hPa, with convergence in the lower layer and divergency in the upper layer.It is conducive to the upward vertical movement of the water vapor.According to the analysis of HYSPLIT model, there are three water vapor transport channels at Lijiang Airport during the rainy season, among which the southwest route accounts for the largest proportion, and the water vapor transport in the Bay of Bengal is the major water vapor source during the rainy season.From July to August, the strong subtropical high and the frequent typhoon activities result in the water vapor transport from the South China Sea, namely the southeast path.Influenced by the Sichuan-Yunnan shear line and southwest vortex, a small amount of water vapor is transported from Sichuan-Chongqing region in August to September, namely the northeast path..