Abstract: The development of groundwater and constructions of water works in Chaohe watershed have great impacts on the runoff yield and concentration. It significantly affected the water resources planning and management in Beijing. The improved Xin'anjiang model is applied to restore the runoff series before 1980, so as to realize the revision of the characteristic value of the design flood. The result revealed that annual rainfall in Chaohe watershed is essentially constant and annual runoff decreased significantly. Storage capacity of basin enhanced significantly. Runoff reduced after 80 years in the same rainfall. Flood peak is higher related with flood volume after 80 years. Maximum daily flood volume is reduced by 11%, maximum three days flood volume is reduced by 17%, maximum seven days flood volume is reduced by 20% and peak discharge is reduced by 6%.The research results can provide important reference value for relevant departments to deal with the development and utilization of water resources under the influence of underlying surface changes.