The invention provides a vacuumizing sealing device for an optical fiber prefabricated rod. The vacuumizing sealing device comprises a vacuumizing housing connected to an optical fiber prefabricated rod extension pipe. The vacuumizing sealing device is characterized in that a sealing groove is formed in the bottom of the vacuumizing housing, and the extension pipe is sealed and nested into the sealing groove; a first sealing component is further arranged on the inner wall of the sealing groove and annularly winds the extension pipe; and a second component is arranged at the bottom of the vacuumizing housing and annularly winds the first sealing component. According to the vacuumizing sealing device, the extension pipe is double sealed from the side, and the two sealing components only bear the friction direction in the radial direction, so that the sealing effect in the prefabricated rod is improved, and meanwhile, the service lives of the sealing components are prolonged.