It is important to identify the non-stationarity in the relation between runoff and sediment load under the backdrop of the changing environment.This relation helps to further understand the mechanisms of runoff and sediment yield.A copula-based method was used to detect possible change points in the relation between runoff and sediment load in the Wei River Basin(WRB),China,where soil erosion is a very severe issue.The modified Mann-Kendall trend test method was applied to obtain the trends of runoff and sediment load spanning 1960-2010 at monthly and annual timescales.Finally,the causes of the identified non-stationarity of the relation between runoff and sediment load were roughly analyzed from the perspective of climate change and human activities.Results indicated that:(1)the runoff and sediment load in the Jinghe and Wei rivers were generally characterized by noticeably decreasing trends at both monthly and annual timescales;(2)both the Jinghe and Wei rivers had a common change point(2002),implying that the stationarity of the relation between runoff and sediment load in the Jinghe and Wei River was invalid;(3)human activities including increasing water consumption and growing application of soil conservation practices are dominant factors resulting in non-stationarity in the relation between runoff and sediment load in the WRB.This study provides a new idea for identifying the non-stationarity of multivariate relation in the hydro-meteorological field under the background of the changing environment. It is important to identify the non-stationarity in the relation between runoff and sediment load under the backdrop of the changing environment.This relation helps to further understand the mechanisms of runoff and sediment yield. A copula-based method was used to detect possible change points in the relation between runoff and sediment load in the Wei River Basin (WRB), China, where soil erosion is a very severe issue. The modified Mann-Kendall trend test method was applied to obtain the trends of runoff and sediment load spanning 1960 -2010 at monthly and annual timescales. Finaally, the causes of the identified non-stationarity of the relation between runoff and sediment load were roughly analyzed from the perspective of climate change and human activities. Results indicate that: (1) the runoff and sediment load in the Jinghe and Wei rivers were generally characterized by noticeably decreasing trends at both monthly and annual timescales; (2) both the Jinghe and Wei rivers had a common change p oint (2002), implying that the stationarity of the relation between runoff and sediment load in the Jinghe and Wei River was invalid; (3) human activities including increasing water consumption and growing application of soil conservation practices are dominant factors resulting in non-stationarity in the relation between runoff and sediment load in the WRB. This study provides a new idea for identifying the non-stationarity of multivariate relation in the hydro-meteorological field under the background of the changing environment.