Abstract: Based on the observation data of upper air and ground at various stations in Inner Mongolia from March 21 to 22,2023,NCEP/NCAR and ERA5 reanalysis data,the causes of the strongest sandstorm weather in Inner Mongolia in the past six years were analyzed.Combined with PM₁₀ concentration data at Hohhot station,HYSPLIT model,potential source contribution factor analysis and concentration weighted trajectory analysis were used to analyze the potential sources of dust and quantify the contribution rate of source areas.The results show that the main influence system of this regional strong sandstorm is the Mongolian cyclone with strong development,and the sandstorm area extends from west to east in a vortex shape,which is closely related to the moving path of the cyclone center.The severity of sandstorm weather in different areas of Inner Mongolia is different,and the change degree of meteorological elements is also different.Visibility and PM₁₀ concentration have a very good inverse(positive) correlation with wind speed.The 300 hPa polar front jet moving eastward and southward is the main high-altitude dynamic system that caused the severe sandstorm.The time,place,intensity and moving path of the severe sandstorm are closely related to the invasion time,intensity and axis position of the jet.On the one hand,the ascending branch of the secondary circulation lifts the dust into the upper air,while the descending branch releases it in the downstream area,on the other hand,it makes the upper air jet flow down to the ground,increases the ground wind speed,and upgrades the dust storm weather intensity.The deep mixed layer is an important stratification feature in the middle and lower troposphere.During this heavy dust weather,the main contribution areas of dust sources are the desert in northern Xinjiang,the desert in southwestern Mongolia and in the north part of central and western Inner Mongolia,which mainly passes through central Inner Mongolia along the southeast path and then affects Beijing and Hebei Province.