A pot experiment was conducted to study the effects of the decomposing walnut(Juglans regia L.) green husk on the growth of Brassica rapa L.var.chinensis seedling group.The results showed as follows:(1)The aboveground fresh weight of B.rapa L.var.chinensis seedling was inhibited significantly by each treatment at 20 d,45 d and 75 d after sowing;(2)The chlorophyll content of B.rapa L.var.chinensis seedling was significantly lower than that in CK at 20 d.As the time extended,the chlorophyll content of B.rapa L.var.chinensis showed a trend of decrease;(3)The activities of superoxide dismutase(SOD) and peroxidase(POD) increased during the observation period,but catalase(CAT) activity did not showed the significant change in 70 d;(4)The contents of soluble protein(SP) and proline(Pro) reduced with the increasing addition of walnut green husk,while the soluble sugar(SS) content was significantly lower than that of CK at 45 d and 75 d.Generally,the allelopathic intensity of walnut green husk on B.rapa L.var.chinensis seedling was strong at early time,but got weaker with prolonged time,and comparatively,high doses of green husk generated allelopathic effects earlier and stronger.