Organic compounds in continuous and alternate cropping soils around rhizosphere of soybean collected at the maturing stage were identified by GC-MS method. The results showed that the continuous and alternate cropping soils contained organic acids, alcohol, ester, ketone, aldehyde, benzene, phenol, hydrocarbon, etc. Many of these were reported as allelopathic compounds. More allelochemicals were found in continuous cropping soil than those in alternate cropping. Most allelochemicals in continuous and alternate cropping soils are the same as those in the root exudates, decomposed root stubs and aqueous extracts from plant shoots of soybean.