Abstract: A phytoplankton-nutrient non-linear dynamic model was constructed for the summer bloom in Xiangxi Bay of Three Gorges Reservoir in Shennongjia area. A general trend of temporal dynamics was reproduced and the pink value of algal biomass was simulated. Several equilibrium conditions with extinction of two kinds of algae were reached by adjusting initial phosphorus concentration. The model can predict the probability and intensity of algal bloom in the water bodies with different trophic levels to some extent. The present study also showed the reflection of variations inside the dynamic system to the real world within limit. Through the management of system parameters, the equilibrium state can be achieved or removed towards the direction that is beneficial to eco-environment.