Abstract: Objective This study aims to reveal the long-term spatiotemporal evolution of sediment connectivity in a typical purple soil small watershed of the Three gorges reservoir area, clarify its response relationship with sediment output, identify the dominant driving factors of spatial differentiation, and provide scientific support for precise soil and water loss control in the reservoir region. Methods Taking the Wangjiaqiao small watershed as the study area, based on remote sensing images, in-situ sediment data from the gauging station, and field sampling data from 2000 to 2022, quantitative investigations on the spatiotemporal patterns of sediment connectivity were conducted using the sediment connectivity index (IC), spatial autocorrelation analysis, hot spot and cold spot analysis, and the geographical detector model. Results During the study period, the sediment connectivity in the watershed exhibited a fluctuating trend followed by a continuous decline, with a significantly accelerated decrease after 2010, closely related to the intensified implementation of ecological restoration programs such as the Grain-for-Green Project. Areas with high connectivity continuously shrank, while low-connectivity areas expanded progressively. The sediment connectivity index showed a significant positive correlation with the suspended sediment concentration at the outlet (r = 0.94), and the detrended analysis still yielded a significant correlation (r = 0.77). Significant differences in sediment connectivity were observed among different land use types and soil types (P < 0.05), with bare rocky land and acid purple soil exhibiting the highest connectivity. Sediment connectivity displayed a pronounced spatial clustering pattern (global Moran's I = 0.790), with hot spots concentrated in gully channels and steep sloping bare lands, while cold spots clustered in gently sloping areas with high vegetation cover. Conclusions In addition to vegetation cover fraction, which is a factor inherently related to the weighting scheme, elevation (q = 0.19), slope aspect (q = 0.17), and land use type (q = 0.12) were identified as important synergistic driving factors. The interactions among multiple factors exhibited synergistic enhancement effects, collectively shaping the spatiotemporal evolution and spatial differentiation patterns of sediment connectivity over the 23-year period. The IC effectively indicates watershed sediment transport at the inter-annual scale, and this study provides a scientific basis for precision soil erosion prevention and control in purple soil small watersheds of the Three gorges reservoir area.