The utility model relates to a laser printer cartridge, which comprises a powder bin, a developing roller, a photosensitive drum and a charging roller, wherein one side of the powder bin is provided with the developing roller. Carbon powder in the powder bin is sent to the developing roller through a powder sending roller and is then attached to the surface of the developing roller. A scraping knife is arranged above the developing roller, and the carbon powder is uniformly scraped and is then attached to the surface of the photosensitive drum. One side of the photosensitive drum is provided with the charging roller, and the charging roller is positioned at a waste powder entrance of a waste powder bin. An upper cover of the powder bin is provided with a powder adding port, and a spring cover piece is arranged above the powder adding port. One end of the spring cover piece is riveted with the upper cover of the powder bin, and the other end of the spring cover piece is provided with a stirring part which is convex to the upper part of the powder adding port and is protruded outside the upper cover of the powder bin. The upper surface of the powder adding port is depressed downwards relatively to the upper surface of the upper cover of the powder bin. A seal washer is arranged between the lower surface of the spring cover piece and the powder adding port, and the upper surface of the seal washer is lower than the upper surface of the upper cover of the powder bin. The lower surface of the spring cover piece is matched with the upper surface of the seal washer, and the lower surface of the spring cover piece and the upper cover of the powder bin are in smooth transition. With the powder adding mode, the laser printer cartridge has convenience in use and a good sealing effect.