In order to explore the medicinal activity of plant resources in Xinjiang.In this study,the antifungal activities of extracts from 21 medicinal plants in Xinjiang were screened and determined by mycelium growth rate method,with Fusarium oxysporum,Rhizoctonia solani and Fusarium verticillioides as target fungi.Then,the ethanol extract of Datura stramoniumwas analyzed and identified by ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS),related databases and literatures.The results showed that among the 21 plant extracts, D. stramonium had good antifungal activity against three cotton pathogens.A total of 21 chemical components of ethanol extract of D. stramonium were identified by LC-MS,The main chemical constituents includedg ten alkaloids,four lipids,two phenolic acids,two organic acids and other compounds.Among them,alkaloids were the main components,accounting for 47.62% of the total.Alkaloids may be the main antifungal components of D. stramonium due to their significant antifungal activity.