Abstract: In order to study the response mechanism in the early stage of seedling growth under Cd stress,the changes of physiological and biochemical indexes were analyzed,which included external morphology,activities of superoxide dismutase (SOD),Peroxidase(POD) catalase (CAT),contents of glutathione (GSH),malondialdehyde (MDA) and chlorophyll (CHL) in 4 kinds of native woody plants(Acer pentaphyllum, Toona ciliata, Alnus cremastogyne, Pinus yunnanensis).The results were showed as below.In terms of external morphology,the underground length of Acer pentaphyllum and Alnus cremastogyne decreased significantly,and the upper part of T.ciliata dropped significantly,and there was no significant change for the ground and underground parts of P.yunnanensis.In SOD activity,Acer pentaphyllum, T.ciliata, Alnus cremastogyne and P.yunnanensis increased significantly with the increase of Cd concentration.As for CAT activity,Acer pentaphyllum, T.ciliata and P.yunnanensis increased significantly with the increase of Cd concentration,while Alnus cremastogyne was significantly higher than that of control group only when Cd concentration was 100 mg·kg^-1.In POD activity,Acer pentaphyllum, T.ciliata, Alnus cremastogyne and P.yunnanensis increased significantly with the increase of Cd concentration.On the GSH side,with the increase of Cd concentration,the contents of Acer pentaphyllum and P.yunnanensis decreased significantly,and T.ciliata and Alnus cremastogyne were not significantly reduced.In terms of MDA and CHL content,these 4 kinds of forest trees showed a significant decrease in high concentration Cd stress,but varied in low concentration.In general,under the stress of cadmium,the seedlings of these 4 kinds of trees changed significantly in terms of physiology and ecology,and showed good tolerance in low concentration.