It was considered that the Permian—Triassic contact in Tianfu area, Chong qing, was conformable, with the paleontology being mixed. But we have found that in this area the contact is usually pseudo conformable and in some places it is slightly unconformable. Both the lithological characters and species of the paleontology above and below the contact are very distinct. Therefore, the Permian—Triassic interface must be the latest corrosive surface of Changxing formation.