Abstract: The seeds were treated by 0(ck),0.25%,1.00%,2.00%,3.00% aqueous extract form Ageratina adenophora in order to investigate the allelopathy on seed germination and growth of Neosinocalamus affinis. The results showed that the aqueous extract of A.adenophora had a significant impact on seed germination and growth of N. affinis. At low concentrations, the aqueous extract improved the germination percentage and germination potential; As the concentration increased, the germination percentage and potential decreased significantly; The fresh weight, root-shoot ratio increased and then fell down; The MDA content and SOD activity were positively related to the concentration of aqueous extract; The POD activity also increased and then fell down, but still higher than those in the control group(0.00%). It suggested that the higher concentration of aqueous extracts would ignificantly inhibit the seed germination and growth of N. affinis, there was a potential threat to the production and operation of bamboo forest.