The aim of this study was to investigate the effects of cadmium(Cd)stress on growth and physiological traits in cyanobacteria Microcystis aeruginosa (M. aeruginosa)and to evaluate the role of nitrogen(N)and phosphorus(P)in cadmium stress alleviation. Microcystis aeruginosa in exponential growth stage was inoculated with different Cd stress concentrations and 3 kinds of nutritive salt for 96h. When cadmium concentration was less than 10 μmol/L, with the increase of the concentration of nitrogen and phosphorus, cadmium stress caused an enhancement in biomass, specific growth rate, chlorop hyll-a(Chl-a), soluble protein, soluble sugar and super oxide dismutase(SOD)activity, and basically the same concentration occurred to the above indexes at 10 μmol/L Cd. The carotenoids had obvious decline just when M. aeruginosa were exposed to 10 μmol/L Cd.