Abstract: A great amount of data have been collected from seabed surface sediment samples, undisturbed box samples and columnar samples, as well as the outdoor vane shear test and soil test in the northern part of the Bohai Bay. The authors summarized the physico-mechanic properties and shearing strength of the surface sediments. Even though there are 7 kinds of surface sediments in the study area, including sand-silt-clay, clayey silt, silt, sandy silt, silty sand, sand and gravel, the undrained shear strength of the surface sediment is larger in the middle part than that in the surrounding areas.