Dramatic water stage rise and channel aggradation in the middle and lower reaches of the Changjiang (Yangtze) River have been recognized by previous studies. A further analysis of the data from geological, geomorphological, and paleohydrological surveys suggests that these changes might have resulted from sea-level rise since the Lateglacial period. So a mathematical model has been developed here, which reconstructs the processes of water-stage rise and channel aggradation of the Changjiang River as responses to sea-level rise since 12,100 a B.P.