A new involute-helix gear drive, which is point contact with convex and concave circular-arc tooth profiles, is proposed in this article. The basic principle characterized by the advantages of involute and circular-arc gears is put forward. Based on the theory of conjugates curves, generation and mathematical model of this new transmission are presented. The separability of center distance on involute-helix gear is discussed and meshing characteristic of point contact is also analyzed. Finally, the three-dimensional solid model of a gear pair is developed to demonstrate the properties of this new transmission.