Abstract: Eastern Depression is the area with the most fierce volcanic activity in Tertiary and with the most volcanic reservoirs in Liaohe basin. Reservoirs were formed by fissure, fissure-porosity and weathering-leaching. Volcanic rocks are laid between good oil-source rocks with great thickness, or capped by the source rocks. Primary and secondary porosity and fissure were well developed in some lithofacies in the volcanic rocks, which provided sufficient space for oil migrating and accumulation. Therefore, the volcanic rocks in the area are favourable for hydrocarbon accumulation. Lava of subaquatic eruption and volcanoclastic rocks near the faults, and volcanic cone are suitable for formation and preservation of reservoirs in the area.