[Objective] Combined permutation entropy and wavelet analysis method was used to analyze the mutation characteristics and influence factors of main stream precipitation sequence in Wei River,aiming to improve water resources utilization of Wei River.[Method] Daily precipitation observation data at four sites (Tianshui,Baoji,Wugong,and Xi'an) from 1960 to 2003 along main stream of Wei River basin were estimated by different sampling sliding window method and the complexity was calculated using permutation entropy method.The evolution of complexity was analyzed to detect the mutations points,and the contributions of different time scales of cyclical fluctuations to precipitation mutation were obtained by sequential decomposition of wavelet analysis.[Result] Tianshui,Baoji,Wugong and Xi'an stations in Wei River basin all had two mutations, which were in 1971 and 1994 at Tianshui station in upstream,while in 1980 and 1994 at Baoji,Wugong and Xi'an stations in midstream and downstream,showing a consistent feature.[Conclusion] The major factor for precipitation mutation in Wei River was periodic fluctuation of climate with the time scale of quasi 10 years.