Analyses of grain size and clay minerals were made for the 626 surficial samples from the western South Yellow Sea. It was found that the sediments in the study area can be classified into the following types:gravel, sand, silty sand, sandy silt, silt, sandy mud, and mud. Based on the sediment origin, the study area is divisible into four districts, that is, fine-grained district around the Old Yellow River in the coast of northern Jiangsu, sandy relict district in the middle and eastern parts of the study area, quasi-relict gravel district in the northwestern part, and the distant part of Shandong subaqueous clinoform in the northeastern part. The clay minerals of the surficial sediments belong to the assemblage of illite-smectite-chlorite-kaolinite, same as the sediments derived from the Yellow River. The silty sand and sand in the middle and eastern parts are all relict deposits in occurrence.