【Background】Ageratina adenophora is one of the worst invasive alien weeds in China. It has caused serious economic losses to agriculture, forestry and livestock, severely damaging the ecology and environment of China′s native habitat. It was confirmed that allelopathy of A.adenophora has been a contributing factor in its invasion, some allelochemicals from A.adenophora have severe negative impacts on the native receptor plants, significantly inhibited the growth of receptor plants. 【Method】The allelopathic effects of aqueous leaf extract of A.adenophora on seed germination and seedling growth of nine herbaceous species in Yunnan Province were determined. These plants included five herbaceous species that compete directly with A.adenophora during the early stage of its invasion: Rumex patientia, Sorghum vulgare, Dactylis glomerata cv.Anba, Vicia dasycarpa and Lepedeza bicolor, and four pasture species introduced to replace A.adenophora: Medicago stive cv.Aohang, Trifolium repens cv.Haifa, T.pratens and Lolium perenne cv.Suda. 【Result】The aqueous leaf extract of A.adenophora could inhibit seed germination and seedling growth in all the nine species, and its effect was concentration dependent, increasing with concentration. Seed germination speed was more sensitive to the extract than seed germination rate, which might be the most sensitive index to judge allelopathy S.vulgare, Lepedeza bicolor and Lolium perenne were not sensitive to the aqueous leaf extracted allelochemicals of A.adenophora. 【Conclusion and significance】Different herbaceous plant species seeds has various sensitivities on effects of aqueous leaf extract of A.adenophora. These results extend our understanding of the invasion mechanism of A.adenophora and to find some potential pasture plants which can displace A.adenophora in invaded regions.