Open AccessIn this study, we 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 cadmium, discussing the interaction effect of cadmium and nitrogen on Populus yunnanensis. The treatments consisted of three cadmium levels (0 mg/kg, 2 mg/kg and 4 mg/kg) and three nitrogen levels (0 mg/kg, 20 mg/kg and 40 mg/kg). After 40 days treatment, the results indicated that at the same nitrogen level, cadmium treatment had significant effects on all measured indexes, including plants growth, chlorophyll concentration, malondialdehyde (MDA) concentration, antioxidant enzymes activities (SOD, POD, CAT and APX), free proline, soluble protein and non-protein thiol. In addition, Populus yunnanensis also showed a certain degree of resistance to cadmium stress. Meanwhile, study also showed there were significant difference among the three levels of nitrogen treatments and the higher nitrogen treatment showed more significant effect of alleviation on cadmium induced damage than that of lower nitrogen treatment in Populus yunnanensis.