Abstract: The effects maceration extract from Solidago canadensis in flower period on seed germination and grow of three crops including Capsicum annuum,Lycoperiscum esculetum and Braxxica chinensis var. communis were determined.The main results are as follows:(1)Strong allelopathic effects of Solidago canadensis in flower period were observed,with facilitating effect on growth of crop seedling under treatment with 25 mg·mL^-1 water extract from Solidago canadensis and the inhibiting effect with 50 mg·mL^-1 or more.The inhibiting effects become stronger with the concentration increase of the water extract from Solidago canadensis,even kill the crop seed with the treatment of 100 mg·mL^-1；（2）The allelopathic effects of the leaves and inflorescences of Solidago canadensis on these three crops are strong than those from the stems;(3)Among these three crop species,the seed of Brassica chinensis var. communis is more sensitive to the water extract of Solidago canadensis than those of Capsicum annuum,Lycoperiscum esculetum.

Key words: Solidago canadensis, allelopathy, seed