Abstract: Tidal river is a land-ocean transitional section with unidirectional water flow and is subject to tidal wave influence. For example, the ~500 km long section between Datong and Jiangyin is regarded as a tidal river in the Yangtze River. Previous studies mainly focused on bathymetric changes based on the scour and sedimentation analysis of the water depth of the chart, while the geometric changes are less reported. Based on remote sensing images for 1989 to 2021, we analyze spatial-temporal changes of the channel geometry for the Datong-Xulujing reaches and quantify changes in the shoreline and channel area. Results show that the length of shorelines increased by ~4.5 km, and area of the islands and sand bars increased by ~96 km2 in the past 30 years. Large islands and sand bars sustain growth while the medium to small-sized islands and bars receded in both number and area. The evolution of the left and right shorelines of the river channel shows their  own characteristics. The left shoreline demonstrates an expansion to the river channel at an average annual rate of 4.10 m/a. The evolution of the right shoreline shows an apparent temporal and spatial distribution. Human activities in terms of reclamation and diking and reduction in sediment load are the main controlling factors of these changes. The outcomes can provide reference for the waterway regulation and river management of the Yangtze River.