Abstract: Grain-size analysis and ²¹⁰Pb dating have been carried out for the sediment samples taken from the two cores drilled in the Jiaozhou Bay. The characteristics of grain-size and their environmental implications are discussed in combination with the sedimentation rate. The results suggest a bilayered structure in the shallow deposits of the Jiaozhou Bay. The upper layer is composed of clayey silt, indicating a weak dynamic environment, whereas the lower layer is composed of gravel-sand and medium coarse sand, indicating a strong dynamic environment. High sedimentation rate is usually related with the sand ridge deposits. Instead, low sedimentation rate is found in channels.