Tooth of roller bit

The utility model discloses a tooth of a roller bit. The tooth comprises a tooth column and a tooth crown which are integrated. The characteristic parameters of the tooth on the roller bit include roller toothed surface half taper angle alpha and a bit shaft tilt angle beta. The tooth crown is provided with a straight line section on a projection outlet in the direction perpendicular to the axis of a drill column, the straight line section and the axis of a toothed column are intersected to form an included angle theta which is equal to the sum of beta and alpha, and the alpha is not equal to the difference between 90 degrees and beta. When the tooth is arranged at the lower position along with rotation of the roller, the straight line section is perpendicular to the axis of the drill column. No matter the tilt angle beta of the bit shaft of the tooth is equal to zero degree or not, and counter acting force on the tooth from rock is parallel to the axis of the drill column, so that the tooth is guaranteed to be only stressed axially and can axially cut without generating side force, stability of the bit is effectively improved, rock breaking efficiency is high, shift of well holes drilled are reduced or even eliminated, and drilling quality is favorably guaranteed.