Abstract: New multi-site daily discharge simulation method need be developed, because more information is needed accompanying with the rapidly increasing construction of reservoirs.In this study, a new multi-site daily flow simulation model was proposed, in which the daily flow of key gauging station was simulated by an autoregressive model.The copula function was built to describe the temporal and spatial dependence between the key gauging station and others.At last, the daily flows of other sites were obtained using the copulas.The upper Yangtze River was selected as a case study.The daily flow of six sites, including the Yichang in the Yangtze River, Pingshan in the Jinshajiang River, Gaochang in the Minjiang River, Lijiawan in the Tuojiang River, Beibei in the Jialingjiang River and Wulong in the Wujiang River, were simulated.The results indicated that the difference of characteristic values between simulated and observed series were small and the proposed method is superior to the current methods.This study provides a new way for stochastic simulation of multisite daily flows.