The correlation between the summer drought/flood in the lower reaches of the Changjiang River and the sea temperature abnormality has been verified by many on-the-spot investigations and observed data. Since Taihu Lake basin is a part of the middle and lower reaches of the Changjiang River, it is questioned whether this kind of correlation existed in historical period. After the analysis of large amount of historical materials, the answer is positive. Finally, combining the historical materials with observed data in flood/drought factor analysis, the model of flood/drought variation in Taihu Lake basin is established.