In this study, we comprehensively compared the rainfall, water level, flood discharge & storage and water project regulation of two flood events occurred in 2016 and 1991 for the Taihu Lake Basin with the method of mathematical statistic. Results show that: (a) Rainfalls leading to floods of these two events were similar in amount and occurring date, but different in temporal distribution, and rainfall in 2016 was severer to flood control than 1991; (b) Influenced by rainfalls, two obvious rising periods of the Taihu water level were observed in 1991, while a continuous rise was observed in 2016; (c) During the flood period of 2016, the water quantity into the Taihu Lake from the Huxi area and the Zhexi area, which are main sources of water into the Taihu Lake, significantly exceeded that of 1991. Besides, the rainfall over the lake area in 2016 also took over that in 1991, which could mostly account for the highest water level of Taihu Lake in 2016 exceeding that in 1991; (d) Fundamental changes have occurred in the drainage pattern of 2016 due to the construction of water projects in the Taihu Lake Basin and methods for regulation also became mature in 2016, resulting in much lower damage accounting for the proportion of GDP caused by floods than 1991.