On the holocene marine accumulated plain of Bohai Gulf, there are two or more series of chenier ridges. Which have been proved to be relict coastlines of different historical times. Their ages were estimated by C-14 dating and archaeological method:the chenier ridge Ⅱ was formed 3100-3500 years B.P., and the chenier ridge Ⅰ was formed 2000 years B. P. The chenier ridge consists of molluscan shells and their fragments. The height of the chenier ridge is usually 2-3 m, because of wind action sometimes reaching 6-7 m. Its maximum thickness is 5 m. The width of the chenier ridge is typically 50- 200 m. In estuarine areas, its width is greater. The following are requisite conditions for the formation of chenier ridges: the beach and shallow are of clayey silt, with a stable slope of 1/100 within the limit of 100 m from the foot of the chenier riage, 1/300 within 100-300 m from its foot seaward, and 1/500-1/600 farther down.