The invention provides an intelligently-controlled boiler system. The system is controlled automatically according to the steam quantity generated by boilers and the water quantity input into the boilers, the boilers are subjected to regular sewage discharging, the sewage discharging speed maintains unchanged, a central diagnosis monitor sets the sewage discharging time automatically according to the specific value between the steam mass and the mass of the water input into the boilers, and thus the discharge capacity is controlled automatically. The input water quantity and the generated steam quantity of each boiler are monitored in real time, the dynamic ratio relation between the input water quantity and the generated steam quantity is obtained, the discharge capacity of the boilers is calculated automatically according to the dynamic proportion relation, and the sewage discharging time is adjusted according to the discharge capacity. Compared with the prior art, hysteresis quality is reduced due to the fact that the sewage discharging time is calculated automatically, and the optimal sewage discharging control can be achieved.