There are 6 Barrie Sand-bars are outcropped or buried on the west coast of Bohai Bay. Based on the geological survey, it is found that the plane distribution features texture of the Barrie Sand-bars, which are from the old to the new are roughly parallel with the coast along the west coast of Bohai Bay (from the coast to the sea).The distribution of the Barrie Sand-bars can be divided into two kinds, one is from the new to the old, and the other one is from the old to the new. In this paper, the division of the Barrie Sand-bars fromⅠ(old) to Ⅵ (new) by using the latter one. Through the description of the material composition and the accumulation characteristics to each Barrie Sand-bar (figure. 2 to figure. 7), conducting the mathematical statistics for the geometrical morphological features (table 2), comparing analysis the formation age features and the division scheme (table 3), summing up the biological assemblages (table 1), the result reveal the occurrence, formation age and the tidal level change of the Barrie Sand-bars fromⅠto Ⅵ (figure. 8). In the basis of the Barrie Sand-bars as a particular geological carrier, the author try to analysis and reveal the genetic mechanism in a macroscopic view, and consider that the generalized Bohai Sea is inland semi-lagoon or local sea in reality. (table. 4 figure. 9) Shangdong Miaodao Island and Liaodong Peninsula constitute barrier coast for Bohai Sea. After comparing analysis to massive data, the barrier coast is an only essential condition to form kebohe delta and beaked delta, both of which may be a possibility condition to form barrier bars (barrier island, barrier beach) or shell ridges. This result is just main genetic mechanism for the shell ridges.