Abstract: Based on the runoff data measured by Jianshan、Shuikou、Hengshan hydrological stations in Meijiang River basin from 1958 to 2000, statistical analysis method is used to analyze inter-annual runoff change characteristics of Meijiang River basin. Based on the data, Mann-Kendall(M-K)test，R/S analysis and Morlet wavelet analysis are used to study its inter-annual variability. The results show that: (1)runoff is mainly focused in May to September from 1958 to 2000; the maximum runoff in June, the minimum runoff in January, and the peak of runoff becomes very obvious from upstream to downstream;(2)runoff of Meijiang River basin shows a trend of increase, in addition to the autumn, the rate of growth fall from upstream to downstream in spring、summer and winter;(3)the mutational site of whole Meijiang River is from 1972 to 1978;(4)quasi-periodic of Meijiang watershed is 4 years, 9 years and 18 years, and it shows in large scale. According to it, the basin has cycle features of much more to less, and there will be less runoff from 2000 to 2018. The results of R/S always show runoff may be reduced in the next period of time in the future.