The consistency of flood series under changing environment is destroyed, which causes the decrease of reliability of design flood calculated based on statistical principle. Therefore, it is urgent to study the design flood revision under inconsistency conditions. Taking the upper Huaihe River Basin as the study area, Pettitt test and moving t-test were used to detect the abrupt change point of the annual maximum peak discharge series. The SWAT distributed hydrological model was applied to restore the series of peak discharge and flood volume before the breakpoint. Based on the simulation results of runoff depth, the design flood was revised, and the revised flood series frequency was analyzed. The results showed that:(1) The insignificant downward trend in annual maximum peak discharge was observed at Xixian and Huaibin Stations in the upper Huaihe River, while an insignificant upward trend was found at Wangjiaba Station. For annual maximum peak discharge, change point at three stations was detected in 1991. (2) The certainty coefficient (R²) and Nash-Sutcliffe efficiency coefficient (NSE) from the three hydrological stations met the applicability requirements. The R² and NSE of the Wangjiaba Station during the calibration period were 0.77 and 0.79, respectively, and the R² and NSE during the validation period were 0.72 and 0.74, respectively, indicating that the simulation accuracy was high. (3) The design flood value from the upper Huaihe River Basin decreased slightly compared with that before the revision. The average decline rate of annual maximum peak discharge was from 3.3% to 6.1%, and the largest decrease rate was found at Huaibin Station. The average decline range of flood volume during different periods was between 1.4% and 2.7%, and the overall revision range was smaller than that of peak discharge. Moreover, the longer the duration of flood volume, the smaller the revision range. With the increase of the recurrence period, the revision range of each flood index decreased gradually. This study is of great significance to the planning of water conservancy projects and flood control and disaster reduction in the Huaihe River Basin under changing environment.