Abstract: The influence of the underlying surface change to the design flood was studied in the Dongwan Basin, Henan Province. Based on the consistency analysis of runoff data from 1970 to 2011,the runoff series change in 1990 was defined as the cut-off point,and the parameters of two series models before and after 1990 were calibrated by Xin'anjiang model. The results show that the underlying surface of Dongwan Basin has changed significantly since 1990,and the change of underlying surface leads to the decrease of runoff. The revised design method of Xin'anjiang model was adopted to revise the peak flow before 1990, the corresponding design flood frequency is about 5% smaller than the average before revision.