Abstract: Abstract: Dali River Basin locates in the middle reaches of the Yellow River Basin, to serve as an important support to the industry and agriculture in northern China. The change of runoff-sediment has become a key issue for the high-quality development of the Yellow River Basin. Since the 1950s, large-scale projects of water and soil conservation have been performed on the middle reaches of the Yellow River, such as Dali River, in order to improve the local ecological environment in the future. Runoff and sediment load have decreased significantly, and the relationship between water and sediment load has changed in recent years. In this study, Mann-Kendall trend test was used to analyze varying trend of runoff sediment load in the Dali River Basin from 1960 to 2015, and then the coordination degree theory and the Pettitt test method were used to clarify the change-point of the relationship between runoff and sediment load. Copula method was selected to verify the obtained change-point data via the joint cumulative probability of runoff and sediment load. The results show that: (1) the runoff and sediment load in the Dali River Basin indicated a significant downward trend at different time scales, such as monthly and annual scales. The variation in runoff and sediment load depended significantly on the external environment; (2) in the relationship between runoff and sediment load, the change-point occurred in 1996, indicating the year of 1996 was a turning point in the management of soil and water loss in the Dali River Basin; (3) after the change-point, both runoff and sediment load were significantly reduced. The reduction was higher than that before the change-point, where the reduction of sediment load was 29.19 percentage points higher than that of runoff, while the contribution of runoff to sediment load decreased by 5.10%, indicating the decrease in sediment transport of runoff per unit; (4) check dam construction and vegetation restoration can be the main factors for the changes of water and sediment load in the Dali River Basin. From 1998 to 2015, Normalized Difference Vegetation Index (NDVI) change in the Dali River Basin has shown a significant increase trend, indicating that the policy of returning farmland to forests has been effectively implemented in local regions. The restoration of vegetation has a positive effect on the reduction of runoff and sediment load. Most check dams have been built in the Dali River Basin, to directly intercept the sediment, while the triggered some changes of runoff, can indirectly prevent the generation and transportation of the sediment. The findings can provide a theoretical basis and promising potentials to clarify the change of water-sediment relationship, the control of soil erosion, and the soil and water conservation in the Dali River Basin, particularly in the Loess Plateau.