Abstract: During the sedimentary period of Ed_3 in Haiyue structure belt in Liaohe tidal area, a series of beach bar sand deposits were formed by the transformation of lakeshore flow and wave in the delta leading edge sand body, which were subdivided into beach sand and dam sand. The beach bar sand is distributed in a strip parallel to the shoreline of the lake, which is easy to form lithologic traps. While the beach bar sand is controlled by many factors, such as the development scale of sand body, reservoir physical properties, fault drainage system and sealing property, etc. In the lower Ed_3 where the beach bar sand is relatively developed,the beach bar sand close to Hainan fault and Gezhou beach fault with superior sealing conditions is most likely to form reservoirs.