Abstract: The dam site flood series of the Danjiangkou reservoir was extended up to 2014 and its greatest historical flood was verified in this study. We checked the design floods using a P3/CF model and P3/LM model separately and obtained a flood limiting water level (FLWL) through reservoir flood routing based on the design flood hydrograph calculated by the P3/CF model. The probable maximum floods were estimated using the envelop curves of the world greatest flood records and the paleofloods in the Hanjiang basin. This rational analysis shows that the historical textual period of the greatest flood occurring in the year 1583 could be extended to a period of 625 years. And by averaging the calculations of these two models, the 1000-year design flood peak and 7-day flood volume should be decreased by 10.4% and 13.3% respectively. Thus we recommend a design flood of 58000 m3/s, a check flood of 80500 m3/s, and an increase in FLWL by 2.0 m for this reservoir. This would significantly increase the comprehensive benefits while ensuring flood control safety of the reservoir.