The utility model discloses a crude oil storage tank foam liquid pipe tail end plugging device which comprises a flange, a screw thread pup joint and an inner screw thread plugging cap, a left port ofthe screw thread pup joint and the flange are connected into an integrated structure, and a right port of the screw thread pup joint and the inner screw thread plugging cap are connected in a screw thread mode. A sealing gasket is arranged at the bottom of an inner cavity of the internal thread plugging cap. The shape of the internal thread plugging cap is designed to be a regular polygon, or theaxial outer end of the internal thread plugging cap is designed to be a regular polygon to be matched with a wrench. The cleaning device is convenient to assemble and disassemble, one person can quickly carry out cleaning operation, the working intensity of operators is relieved, the maintenance time is shortened, and the working efficiency is improved.