West Southern Xinjiang,as the bridge tower of the Belt and Road,frequently happened severe rainstorm in recent years brought big agricultural economic loss,and extremely restricted the construction process of the silk road economic belt in west Southern Xinjiang.In order to further understand the reasons for the formation of heavy rainstorm of west Southern Xinjiang in the late spring and early summer,and improve the forecast accuracy of fixed point and quantitative precipitation,the similarities and differences of atmospheric vertical straight structure and characteristics of water vapor of the two heavy rain weather processes happened on late spring and early summer,namely 1st-4th and 26th-29th May,2016,were analyzed by using 15 meteorological stations and 200 regional automatic weather stations daily precipitation data in western Southern Xinjiang(35-42N,73-80E),and NECP/NCAR daily 1 degree resolution reanalysis data.The results indicate these two heavy rain weather processes were happened in the case of triggered uplifting of LLEJ,which was influenced by the Central Asia south vortex.The main source of the water vapor was distributed in the Arabian Sea and the Bay of Bengal.On May 1st-4th,the main water vapor transport path was eastward and southwest airflow,which was strongly converged in the west of Southern Xinjiang along the mountain and eastward plain,and caused the heavy rain.The duration of the high value region of the water vapor transport was 24 hours.On May 26th-29th,there are three water vapor transport paths,namely west,southwest and eastward.These three water vapor transports converged intensively in western Southern Xinjiang in east-west and south-north direction and caused large scope strong rainstorm weather.The duration of the high value region of the water vapor transport was 60 hours.