The invention discloses a novel tooth-shaped screw type wire, which belongs to the technical field of dry type screw vacuum pumps. The screw type wire disclosed by the invention comprises 5 curve segments, including a dedendum arc ab, a deformed involute bc, an envelop curve cd of a deformed involute b'c', an addendum arc de and a long cycloid ea, wherein the dedendum arc ab and the deformed involute bc are in smooth transition, and the envelop curve cd and the addendum arc are in smooth transition. According to the screw type wire disclosed by the invention, the deformed involutes and the envelop curve are taken as transition curves between the dedendum arc and the addendum arc, so that the dedendum arc and the addendum arc are in smooth connection with the transition curves to prevent a leakage zone and a stagnation zone and to form tight sealing, and the change of a formed end face prompts the improvement of dynamic performance; and simultaneously, the dedendum and the tooth profile part of a rotor are in smooth connection by virtue of the transition curves, and thus manufacturing costs are effectively reduced. The dry type screw vacuum pump provided by the invention can be widely applied to the fields of electronics, semiconductors, chemical industry, food, aerospace and the like.