The bottom sediments and water samples of Kangjin bay area, southern coast of Korea, which is characterized by semi-enclosed and mesotidal regime were analyzed to delineate the source and transportation of surface sediments, the characteristics of surface sediments and depositional environment. The surface sediments which consist of silt, sandy silt, gravelly muddy sand, slightly gravelly muddy sand, gravelly sand, gravelly mud, and mud in the study area, could be defined with three fades ; sand fades, mud fades and gravel facies. The depositional environment is interpreted as channel and mud flat. Based on the occurrence of silicoflagellates in biogenic sediments and mineral constitnents including quartz, orthoclase and plagioclase, and suspended Particulate matter, it is indicated that the most of the surface sediments in Kangjin bay are transported from Tamjin river, and the minor part by tidal current after reworking and transportation from offshore area.