In order to improve the control quality of the water level for steam generator, a fuzzy level controller for steam generator is designed based on the fuzzy logic principle. The fuzzy logic toolbox and Simulink module of Matlab software are used for the modeling of the water level control system of steam generator. The operating condition of reducing load is calculated. Simulation result shows that the fuzzy control has such virtues as smaller overshoot, shorter regulating time and stronger robustness than the conventional three-element PID control. Fuzzy control is especially effective for nonlinear system like steam generator with multivariable, large time lagged and strong coupling. It is a very effective control method with widely application prospect.