To grasp the evolution characteristics of the annual runoff and sediment in the Jinghe River Basin, moving average test was applied to analyze multi-year and annual variation based on annual runoff and sediment of Zhangjiashan Hydrological Station, and moving correlation analysis and double mass curve were used to detect the abrupt change point of the relationship of flow-sediment. With P-III curve method and popular Copula-constructed two-dimensional joint distribution of runoff and sediment, the variation characteristics of runoff and sediment were analyzed, and the encounter probability of rich-poor runoff and sediment in different periods were calculated. Results showed that: the alteration of runoff- sediment relationship occurred in 1980s. Compared to the period of 1956-1982, the mean value of runoff and sediment decreased by 29.10% and 29.45% in 1983-2010. When P is less than 90%, the annual flow and runoff keep decreasing, and when P exceeds 90%, the flow decreases and the sediment keeps increasing. The designed value of water and sediment should be corrected. In different periods the synchronous frequency of both rich and poor was greater than the frequency of rich-poor, and the probability of rich-poor was the smallest (0.35% and 1.10% respectively in different periods). In the period of 1983- 2010, the frequencies of different combinations become more even. The study can provide technical support for water and sediment disaster reduction and project management.