The antibiotic experiment of extractive from Allium fistulosum and Allium tuberosum root with petroleumether and ethylacetate against Fusarium oxysporum f.sp.cubense was investigated.The results showed that the most conspicuous inhibitory effect on the germ was from the extract with petroleumether from Allium fistulosum stem.Compositions of the extract were analyzed by GC-MS，in which two main compounds,disulfide（42.07%） and thioxane（16.29%） were obtained.The extracts with petroleumether from all the parts of Allium fistulosum and Allium tuberosum root，as well as the secretions in water of Allium fistulosum and root of Allium tuberosum dissolved with ethylacetate were further detected by GC-MS.The secretions detected from petroleumether were 24，9，11，27，and those from the ethylacetate were 19 and 7.The petroleumether extracts contained many sulfocompounds，which were mainly the disulfide，occupying 31.09% in Allium fistulosum root，42.07% in stem and 26.20% in leaf，but little in Allium tuberosum root.Compounds containing carbazole were detected from secretions in water of Allium fistulosum root，up to 28.03%，and phenethylamine，benzeneacetic acid，cyclohexene-1-one semicarbazone，indole etc.were detected from secretions in water of Allium tuberosum root.