This study focused on the spatio-temporal variation of precipitation in the cascade hydropower development zone in the lower reaches of the Jinsha River. The changing trends, periodic oscillation, and duration characteristics of multi-annual and seasonal precipitation were analyzed using linear trend analysis, Morlet wavelet analysis, and R/S analysis methods, based on monthly precipitation data of ten meteorological stations in the study area during the period from 1956 to 2011. The results show that the annual precipitation in the study area during the period from 1956 to 2011 has shown a fluctuant downward trend at a tendency rate of -1. 338 mm per year. The precipitation increased slightly in spring and decreased in summer, autumn, and winter, with significant spatial differences. The precipitation in summer and autumn accounted for 81. 1% of the annual precipitation, especially the precipitation in summer, which was the leading factor accounting for 57. 4% of the annual precipitation. The periodic oscillation of annual precipitation was concentrated in one to two years, expectant four years, eight years, 14 years, and 31 years, and especially in expectant eight years, which was verified by a 90% confidence level test. There was an obvious Hurst effect of the precipitation series in the study area, with a feature of persistence in general, and the precipitation will maintain a decreasing trend in the future.