Abstract: The Lishu Depression of the Songliao Basin can be divided into a faultdown depressionstructural sequence in the lower part and a depression structural sequence in the upperpart.The faultdown depression structural sequence could consist of four sub-sequences ofthe lower and middle parts of the Shahezi Formation,the Yingcheng Formation and theDeng louku Formation.In lower part of deep faultdown depression,the alluvial fan-fandelta system,delta system and lacustrine system are widespreaded,of which lacustrinesedimentary system takes a large proportion and could be considered as the main sourcerocks of hydrocarbons in the Lishu Depression,while the plaiting plains-type fan delta sandmassif and delta sand massif could be the main reservoirs in deep faultdown depression.This paper describes the stratigraphic sequence and petroliferous characters of deep fault-down depression based on the geological studies of the depositional systems and the forma-tion of sedimentary sequences.