Abstract: Microystis aeruginosa was cultured in solutions of different initial nitrogen and phosphorus concentrations. The semi-saturation constants (Ks) of Microystis aeruginosa to P and N were calculated respectively by using the Monod equation. The results show that the Microystis aeruginosa grew normally when the concentrations of N and P were greater than 4.0 mg·L^-1 and mg·L^-1 respectively. The optimum concentration ranges of N and P for Microystis aeruginosa growth were 32.0~64.0 mg·L^-1 and 1.0~1.50 mg·L^-1 respectively. Ks_N is higher than Ks_p,  which indicates that the affinity of P to Microystis aeruginosa is higher than N. When the concentration ranges of N and P were 0.20~64.0 mg·L^-1 and 0.02~1.50 mg·L^-1 respectively，they had high liner correlation with the largest extent quantity of Microystis aeruginosa. The special growth rate increases continuously when the concentration ranges of N and P are 0.20~1.60 mg·L^-1 and 0.02~0.50 mg·L^-1 respectively.

Key words: Microcystis aeruginosa, nitrogen, phosphorus, growth characteristics