Abstract: A hinge comprises an upper blade; a receiving portion installed at one lateral side of the upper blade; the receiving portion having an opening facing downwards; an interior of the receiving portion having a stepped hole; the receiving portion being at the same level as the upper blade; a first assembly block installed at another lateral side of the upper blade; a lower blade; a positioning portion located at one lateral side of the lower blade; the positioning portion having an opening facing upwards; an inner wall of the positioning portion being installed with annular teeth; the positioning portion being at the same level as the lower blade; a second assembly block being at another lateral side of the lower blade; a supporting pivotal shaft having an upper sliding inclined surface and a positioning teeth portion. The hinge can be installed at the interior or exterior of a doorplate.