A tube joint for connecting two pipes comprises two enlarged openings formed at two pipes to be connected; a sealing pad between the two enlarged openings; each of two ends of the sealing pad are formed with a reduced stepped portion; a shape of the stepped portion being matched to the enlarged openings so as to be received in the enlarged opening; thereby the stepped portion can seal the enlarged opening; a middle section of the sealing pad being between the two reduced stepped portion and being protruded between the two enlarged openings; and two covering plates. Each covering plate encloses around a periphery of the enlarged opening and a periphery of the middle section of the sealing pad. Two first annular lips are installed around an outer periphery of the stepped portions of the sealing pad, and each sealing pad may be formed with a second annular lip.