In order to understand the evolution of modern tidal sand ridges, this paper studied the development of radial sand ridges and the movement of suspended sediments around sand ridges in northern Jiangsu (Subei) Coast, China, by use of multi-temporal satellite images, bathymetric maps and field data. The results showed that the total number of radial sand ridges off Subei coast especially the number of small sand ridges (no more than 10km² in area) increased significantly while total area and average area of sand ridges decreased sharply. High content of suspended sediments frequently existed in the center of the radial sand ridges, and the suspended sediments moving towards there resulted in the accumulation of sand there and erosion of outer sand ridges. Radial sand ridges are in the stage of breaking-down and shrinking on the whole. The distribution and diffusion of suspended sediments plays an important role in the evolution and stability of sand ridges. The increase or decrease in net sand transport indicates accumulation or erosion of sand ridges