Sediment connectivity reflects the connectivity between sediment sources and sinks and contributes to understanding soil erosion and sediment transport processes. However, the potential effects of climatic factors and vegetation restoration on sediment connectivity have not been fully recognized, especially in the karst area of southwest China, which has a serious rocky desertification and fragile ecological environment. This study aims to quantify the connectivity index (IC), runoff, and sediment yield changes induced by the coupling impacts of climate change and vegetation restoration in six typical karst watersheds. Annual climate, vegetation, land use, soil, runoff, and sediment yield data were collected during 2000 similar to 2019. The parameters of IC were calculated based on the source-sink landscape index. The Partial least squares structural equation model (PLS-SEM) was used to quantify the impacts of climate change and vegetation restoration on changes in IC, runoff, and sediment yield. The results show that the average IC value ranged from 2.10 to 2.97 during 2000 similar to 2019, with an insignificant decreasing trend. PLS-SEM analysis shows that climatic and vegetation factors explained 1 similar to 7 % of the changes in IC values and 53 %similar to 90 % of the runoff dynamics. Climate factors, vegetation dynamics, runoff, and IC values together explained 21 %similar to 67 % of the variations in sediment yield. These results can facilitate understanding the temporal variation in IC and are significant for ecological restoration and sediment delivery control in karst areas.