A study on hydrocarbon accumulation conditions in the Liaodong Bay depression is performed based on analysis of source rock，reservoirs，reservoirseal assemblage，traps and carrier systems.The results show that there are three sets of source rocks，including the 3rd and 1st member of the Shahejie Formation and the 3rd member of the Dongying Formation.Among them，the 3rd member of the Shahejie Formation is the major source rock.Both basement and clastic reservoirs exist and are of high quality.The main types of sourcereservoircap rock assemblages include indigenous generation and accumulation

，lowergeneration and upperaccumulation and generationinthenew and accumulationintheold.Faults dominate the carrier system and connect source rocks and unconformities which are separate in time and space，forming a faultunconformity carrier system.Traps were mainly developed during the deposition of the Paleogene Shehejie and Dongying Formations.They are mostly syndepositional structural traps and are rarely pure lithologic traps.Horizontally，oil and gas pools distribute along the TanLu Fault zone and are featured by zonation in NS direction and segmentation in EW direction.Low salient structures are rich in oil and gas.Vertically，oil/gasbearing layers become younger and shallower from north to south.