The flood season is usually divided into several stages in reservoir operation for the sake of more benefits. This paper presents a method of flood season staged for the Three Gorges Reservoir based on the change-point theory. Two methods of analyzing change-point, which assume the data set follows the normal distribution and binomial distribution respectively, are applied in daily discharge data of the Yichang Gauging Station from 1882 to 2001. The results indicate that the flood season staged for Three Gorges Reservoir is divided into three periods. By analysis, the change-point method based on binomial model is more suitable in flood season staged since it has theoretic basis and is practicable.