To accurately collect the service life data of disc cutters of tunnel boring machines(TBMs),  the consumption and cumulative wear of disc cutters of TBM boring in hard rock tunnel section of the Bid 2 of the Chaoer river to Xiliao river water conveyance project are counted. Then, the concept of equivalent replacement times of disc cutter is introduced to calculate the cutter service life based on cutter wear limit value. According to the stratigraphic changes along the tunnel line, the variation rule of cutter service life in granite and tuff rocks with different grades is analyzed, and the correlation between disc cutter service life and uniaxial compressive strength and rock volume joint number in grades Ⅱ and Ⅲ surrounding rocks is obtained. The results show the following: (1) The cutter equivalent replacement times can accurately calculate the cutter service life in different strata and reflect the proportions of abnormal failure cutters in different rocks. (2) In grades Ⅱ and Ⅲ surrounding rocks, the cutter service life has a negative power function relationship with rock strength and a positive power function relationship with rock volume joint number. With the decrease of rock strength and the development of rock joint, the cutter service life gradually increases. (3) In grade Ⅳ surrounding rock, the factors affecting the cutter wear are complex, the proportion of the abnormal failure cutters is large, and the cutter service life decreases.