Abstract: Three layers of shallow marine clays with different sedimentary history are observed in Lianyungang area. The upper layer of the soft marine clays is a major concern in engineering practice because of possible settlement and stability problems of embankment built over it. This paper assessed the sediment environment of soft marine clays and their physical and mechanical properties. The shallow marine clays were formed chronically in the Holocene between Huanghua (the Yellow Sea) transgression and 1860,s A.D. The statistical results show that the clays have high water contents, and the ratio of their vane test strength vs. the effective overburden pressure ranges from 0.2 to 0.4. Burland,s void index and intrinsic compression line are then used to characterize structures of the marine clays. It is concluded that highly structured clays can be easily disturbed, and the laboratory strength is distorted.