Abstract: In this paper, we investigated the effects of root exudates of the Astragalus membranaceus Bge.var.mongholicus(Bge.) Hsiao on its seed germination and seedling growth.The results showed that the root exudates of Astragalus mongholicus significantly inhibited the seed germination and seedling growth.Compared with the control the germination rate, germination potential and germination index in the root exudates treatment were reduced by 43.6%, 34.0% and 59.6%, respectively.The original extract of root exudates had the strongest allelopathic effect on the seedlings of Astragalus membranaceus.The root exudates enhanced superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities.When the dilution of root exudates was less than 0.6, the protective enzyme activity decreased as the root exudates dilution decreased, and the extract solution had the lowest protective enzyme activity.The content of malondialdehyde (MDA) of seedlings was increased with the increment of extract concentration.When the dilution of root exudates was less than 0.6, the allelopathic autotoxicity effects of Astragalus mongholicus were increased with increased concentration of the root exudates.