In order to explore the distribution characteristics of sediment grain size and clay mineral in Caofeidian inshore, China, 15 sediment samples were collected from Caofeidian inshore, and tested based on the laser particle size analysis and X-ray diffraction(XRD)analysis. Results show that the sediment of Caofeidian inshore is mainly composed of silt(45.2%), followed by sand(30.2%)and clay(24.6%).The sediments of Caofeidian inshore are in the order of illite(55.8%)>smectite(24.9%)>chlorite(9.9%)>kaolinite(6.7%)in clay minerals. The characteristics of the surface sediments are affected by natural factors, such as the provenance and hydrodynamic and human factors such as reclamation engineering and others. The long-term large-scale reclamation engineering reclamation obviously affect the finer particles(silt and clay)distribution of surface sediment. The distribution characteristics of clay mineral(illite, kaolinite and chlorite)are closely related to the change of hydrodynamic caused by reclamation
