The macroscopical and histological findings on a rare of malformed teeth occured in the left first Molar of upper jaw of the sixteen years old boy who is examined at the dental clinic of Soodo medical college are summerized as follows. 1.Occulusal surfare of the malformed teeth formed as circumvallated hard tissue wall and root are hypertrophical type. 2. The tissue of malformed teeth occured dystrophy of calcication distavance.