Abstract: Based on the different grinding process parameters of K9 glass, the law of the change of the depth of grinding damage layer with the process parameters is determined, and the crack propagation law is studied through the dynamic detection of the depth of grinding damage layer of the workpiece. The results show that the crack damage in grinding process is a dynamic propagation process. Under the fixed process parameters, the crack propagates steadily so that the depth of the damaged layer remains constant. When the grinding process parameters with less damage are used, the crack growth speed is less than the material removal speed, and hence the depth of damage layer is gradually reduced. The removal speed of damage layer is gradually slowed down until a balance between the growth speed and the removal speed. At the same time, in order to remove the damage layer of one process, the material removal amount of the next process should be 2 to 3 times of the damage layer depth of the previous process.