Atractylodes lancea plants were cultivated in pots in a greenhouse in order to study on the mechanisms of plant autotoxicity. The soil used in the experiment was freshly collected from a bare field. After 8 months, A. lancea was harvested. Treatments of H2O, 10, 50, 200 mg/ml extracts of rhizoma and 50, 200, 500 mg/ml extracts of rhizosphere soil were applied to test their effects on early development of A. lancea. Seed germination rates, extension of radicle and embryo, were recorded respectively at 5 d, 7 d and 14 d after emergence, then one-way ANOVA and multiple comparisons were conducted to test the differences between the treatments. In the follow-up studies, both rhizoma and rhizosphere soil were extracted by diethyl ether and ethyl acetate respectively, and GC-MS was conducted for the identification of the compounds in the extracts, and the similarity of the composition of compounds in rhizoma and rhizosphere soil by same extraction procedure were compared with Jaccard coefficient.β-eudesmol, which was found to be the major component in extracts of A. lancea rhizoma, was used to test the bioactivity. The experimental results showed that ① Neither 50 mg/ml and 200 nor 500 mg/ml extracts of rhizosphere soil had influences on seed germinations or the development of radicles and embryos；② Germination rates, lengths of radicles and embryos decreased with increasing concentration of rhizoma extracts，and 200 mg/ml rhizoma extracts reduced A. lancea growth significantly (p＜0.05). Germination rates, lengths of radicles and embryos under this treatment was 11%, 32% and 23% of the controls respectively. ③ 20 compounds in rhizoma extracts and 27 compounds in rhizosphere soil extracts were identified. Many compounds, such as 2,5-octadecadly3noic acid, methyl ester，n-Hexadecanoic acid，Pentadecanal，Tetradecanoic acid，1-Naphthalenol，Butylated Hydroxytoluene，2-Methoxy-4-vinylphenol，etc., were allelophathic substances and detected in both extracts of rhizoma and rhizosphere soil.β-eudesmol and Hinesol, which were the main components of essential oil in A. lancea, was found in rhizoma extracts. ④ It was found that β-eudesmol, terpene, most of which are allelophathic substance, at all concentrations, had no effect on the germination rates and lengths of radicles，but 100 and 250 mg/l β-eudesmol reduced embryo development significantly. In conclusion, there was autotoxicity in continuous cropping of A. lancea, which was one of the causes of problems associated with continues cropping of a singl e plant species.