Abstract: The channel-sandbar system (CSS) is a common geomorphic combination of rivers, and its development and evolution may pose a threat to safety of navigation, water-related engineering, and flood control. The evolution of CSS involves both subaerial and subaqueous parts. Accurately calculating the amount of topographic change remains a challenge in geomorphology. This study took the CSS of Zhangjiazhou reach of the Yangtze River as an example. The joint changes in the volume of subaerial sandbars and subaqueous channel-sandbars were considered. Based on navigation reference plane and the measured water level at hydrological stations, remote sensing images and navigation maps were corrected to a unified elevation reference. An integrated digital elevation model (DEM) for the evolution of CSS volume was developed. The results indicated that this method could efficiently calculate the volume changes of the CSS. From 1993 to 2019, the changes of CSS in the study area was indicated as erosion (12.85 × 106m3 in 1993-2008), siltation (8.14 × 106m3 in 2008-2013), and siltation (15.72 × 106m3 in 2013-2019). Overall, the volume of the CSS in the study area increased by 11.77 × 106m3 during 1993-2019, which was equivalent to 14.12 × 106 t of sediment deposition, using a sediment bulk density of 1.2 t/m3.