The utility model discloses a pipeline end socket convenient to observe inside, which comprises a support device, extension devices are fixedly mounted on two sides of the support device, positioning devices are slidably sleeved on the extension devices, each extension device comprises an extension support, an alignment plate, a vertical guide rail and an anti-drop piece, the alignment plate is fixedly installed at the side end of the extending support, the vertical guide rail is fixedly installed at the bottom of the front end of the extending support, the anti-disengaging piece is fixedly installed in the center of the bottom end of the vertical guide rail, the supporting device comprises a pipeline, supporting base plates and a second sealing strip, the supporting base plates are fixedly installed on the two sides of the pipeline, and the second sealing strip is fixedly installed on the supporting base plates. The second sealing strip is fixedly installed at the front end of the pipeline, and the positioning device comprises a supporting transverse frame, a front guiding rod, a hydraulic air cylinder, a limiting inserting rod, a sleeve plate, a first sealing strip and a pipeline sealing head. Through the arrangement of the extension device and the positioning device, the purpose that the interior of the pipeline end socket can be observed rapidly is achieved.