In this study, researchers used Populus yunnanensis, a native precious poplar species which is only distributed in Southwestern China as a model species to study its morphological, physiological and biochemical responses to the interaction of different concentrations of nitrogen and Cd, discussing the detoxification effect of nitrogen to Cd stress in Populus yunnanensis. The treatments were consisted of three Cd levels (0, 2 and 4 mg kg-1) and three N levels (0, 20 and 40 mg kg-1). After 40 days treatment, the results indicated that at the same N level, Cd treatment had significant effect on all measured parameters, including plant growth, chlorophyll concentration, Malondialdehyde (MDA) concentration, antioxidant enzymes activities (SOD, POD, CAT and APX) and free proline. Meanwhile, study also showed there was significant difference among the three levels of N treatment. With the increasing concentration of N supplement, it showed more significant effect of alleviation to Cd induced damage in Populus yunnanensis.