The invention discloses a method for reducing abnormal damage of a hob in the tunnel excavating process of a shield machine. In the method, critical minimum penetration and critical maximum penetration of the shield machine in the excavating process are calculated by acquiring relevant parameters of the hob and stratigraphic rocks, so that the thrust of the shield machine in the excavating process is adjusted to control the actual penetration to be in the range of the critical minimum penetration and the critical maximum penetration. In the method, the penetration range can be adjusted according to the change of the rock strength and the cutter wear condition in the excavating process to be controlled to between the critical minimum penetration and the critical maximum penetration, so that the abnormal damage of the hob in the hard rock excavating process of the shield machine is reduced, the rock-breaking efficiency of the hob is improved, the design and the arrangement of the cutters are improved, the excavating parameters are optimized, and the like.