Scuffing is a common failure for the high-speed gears, which cannot be accurately predicted by current criteria. The purpose of this paper is to investigate the anti-scuffing capacity of the helical gear pairs considering profile modification. A series of comparative tests under the same lubrication and operating conditions were proposed for these test gearsets, which have the same macrogeometry and different modification. In doing so, the effects of relief amount, the starting point of profile modification and the type of tip relief on the anti-scuffing capacity of gears are obtained. In addition, it is found that scuffing also has a “direction” with sliding, and is more prone to occur when meshes out by observing the surface of scuffing.