Based on the measured runoff and sediment data of six hydrologic stations (Pingshan, Zhutuo, Cuntan, Yichang, Hankou and Datong) situated at Yangtze River’s main stream, this study analyzed the inter- and intra- annual variation trends of runoff and sediment during 2001-2018 and their causes using statistical methods including linear regression, Mann-Kendall test, Sen’s estimation and accumulative anomaly. The results showed that since 2000, the annual sediment discharge of each hydrologic station significantly declined compared with that before 2000, with the decreasing amplitude higher than 56%, while annual runoff decreased insignificantly with the decreasing amplitude lower than 8%. The variability of sediment discharge was higher than that of runoff. For the Yangtze River basin, from 2001 to 2018, the average monthly runoff and sediment discharge was 718×10⁸ m³ and 1 247×10⁴ t, respectively, and mainly distributed between June and September. The trend analysis indicated that annual precipitation and runoff had no remarkable changes, however, annual sediment discharge showed a significantly decreasing trend. The change-points for Pingshan, Zhutuo and Cuntan station were in 2010 and 2012, and those for Yichang, Hankou, and Datong station were in 2005. Monthly runoff for Pingshan station had no obvious trends; for Datong station, runoff only increased significantly in January, that of the other four stations increased significantly between January and April. Monthly sediment discharge from June to October for the six stations showed significant decreasing trends. In this study, human activities such as water conservancy construction and soil and water conservation were the primary causes of sediment reduction in the Yangtze River basin.