Gear transmission is the most widely used transmission form in shearer. It has the characteristics of accurate transmission, high efficiency, compact structure, safe and reliable work, long service life and so on. The manufacturing level of gears also reflects the technical level of an enterprise producing shearers. With the development of shearers to high-power models, gear transmission is also developing in the direction of high precision, large load-bearing and long life. However, gears are subject to many factors such as load, working environment and so on. The tooth root of shearer is easy to be ground because the tooth root is not ground. The tooth root is discussed by analyzing the design of the Hob, the allowance of the retained grinding, the parameter setting of the gear grinder and the deformation of heat treatment. At the same time solving a major problem of how to avoid grinding the tooth root and grinding steps in the actual production of gears, and also lays a solid foundation for improving the service life of gears.