Abstract: The shelly layers in Chuanganglu pit of Dagang District on the west coast of Bohai Bay were taken as the study object for investigating the residence time of the Holocene reworked shells. Based on an analysis of the AMS 14C dating results of 15 samples, including articulated, disarticulated valves and shell hash, which were taken from the three shelly layers of five sections (Section 2 and sections 4~7), the authors obtained the residence time of 440a for the disarticulated shells and 650a for the shell fragments, on the basis of a comparison with the ages of the articulated shells taken from the same layers.