Abstract: The relationship of continuous cropping obstacle and allelopathy of Polygonatum was studied through the biology tests of soil extracting solution and the isolation and identification of organic compounds. Extracting method was used to prepare rhizosphere soil extracting solution of Polygonatum, indoor biological assay method was used to measure allelopathy and GC-MS was used to identify the organic compounds. The results showed that the rhizosphere soil extracting solution of Polygonatum could significantly inhibit the rhizome spore germination rate, seedling height and root fresh weight, and with the increase of extraction solution concentration, the inhibition was enhanced. 24 kinds of compounds were identified in the extracting solution, including organic acids, ketones, aldehydes and so on, many of which had been reported to be allelochemicals. Rhizosphere soil extracting solution of Polygonatum had obvious allelopathy on rhizome spore germination rate and seedling growth, and the self-poison effect had dependency on concentration, indicating that allelopathy was the reason that caused continuous cropping obstacle of Polygonatum.