The invention relates to the technical field of connecting pieces and discloses a long-service life pipeline connecting piece. The long-service life pipeline connecting piece comprises an installationbase. The outer surface of the installation base is in threaded connection with a casing pipe. The outer surface of the casing pipe is fixedly connected with protrusions. The casing pipe is fixedly connected with a fixing ring through the protrusions. The inner bottom wall of the fixing ring is fixedly connected with a rubber ring. The top of the fixing ring is fixedly connected with an upper hold-down ring. The surface of the upper hold-down ring is fixedly connected with an antirust coat. The inner wall of the installation base is fixedly connected with an L-shaped connection piece. One side of the L-shaped connection piece is provided with an anticorrosive layer. According to the long-service life pipeline connecting piece, the protrusions, a sealing cushion, the rubber ring, the fixing ring, the upper hold-down ring, a lower hold-down ring, the L-shaped connection piece and the anticorrosive layer can play a sealing role at a pipeline joint, fluid in the pipeline is prevented fromleaking at the pipeline joint, the anticorrosive layer formed by weather-proof glue can also play a very good corrosion resisting role while playing a sealing role, and the service life of the deviceis prolonged.