Abstract: A long-lasting self-lubricating large oil barrel includes a sliding a sliding track, a sliding housing and an oil storage tank. The oil storage tank has oil piths, and weight members a lubricating oil at an interior thereof. Using capillarity of the oil piths, the lubricating oil is evenly absorbed and distributed within an oil-containing sponge. With displacement of the oil-containing sponge at the sliding track, the lubricating oil is proportionally applied to the sliding track, thereby accomplishing long-lasting and smooth lubricating effects when a roller is rolled at the sliding track. Using weight of the weight members, the ends of the oil piths are maintained at lowest positions of in the oil storage tank, thereby enabling the oil storage tank to supply the lubricating oil according to different installation directions of the sliding housing and the sliding track to achieve thorough lubricating effects.