Gear shaving is a gear finishing operation of high efficiency and high precision. After shaved by shaving cutter of true involute profile, there are the "mid-concave" phenomena around the pitch points of the work gear tooth flanks inevitably. This problem severely affects the shaving accuracy and gear transmission quality, which hasn't been resolved thoroughly for a long time. Aiming at the problem, based on shaving mechanism and the analysis on gear tooth profile mid-concave, a new-style shaving cutter with unequal depth gashes is designed and manufactured. As compared with common shaving cutter, its depth of gashes is zero on the pitch points of tooth profiles and gradually gets deeper to max. from pitch points to the tops of teeth or the roots. Because of no depth on the pitch points, there are no cutting edges, that is, no cutting action, so the work gear isn't cutted around its pitch points and is only pressed during shaving operation. Therefore, the gear tooth errors are decreased greatly. And the experimentations have proved the shaved gear has better surface finish that achieves the expectant effect. In addition, this paper analyses the forming of gash on the basis of slotting principle, and proposes a design method of gash: gash bottom is formed by two involutes which intersect on the pitch point and are concentric with the base circle of involute profile of cutter. Furthermore, the equations of the two involutes are deduced and the solution is introduced. This paper analyses the forming of gash on the basis of slotting principle, and proposes a gash-designing method. And the experiment has proved that the shaved gear has better surface finish that achieves the anticipated effect.