In order to provide a theoretical basis for the development of new plant virus inhibitors,the chemical components of Senecio scandens and its activity against tobacco mosaic virus (TMV) were determined.The chemical constituents of the ethyl acetate extract from the aboveground part of S. scandens were separated by silica gel,Sephadex LH-20,MCI and other column chromatography methods,and its structures were identified by NMR and MS data.The inhibitory activity of the compound against TMV was screened by the half-leaf spot method in vivo.Thirteen compounds were isolated from the ethyl acetate extract of S. scandens. According to their physicochemical properties and spectral data,they were identified as 9,19-cyclolanost-24-en-3-one (1),7β-methoxystigmast-5-en-3β-ol (2),dotriacontane (3),ursolic acid (4),stigmasterol (5),(22E)-ergosta-6,22-diene-3β,5β,8α-triol (6),kaempferol (7),indole-3-carboxaldehyde (8),nepetin (9),quetrcetin (10),taxifolin (11),jacaranone (12),phytol (13).Except compound 7 and compound 10,the other compounds were isolated from this plant for the first time.The results showed that compound 8 and compound 13 had strong anti-TMV activity.