Disc cutters are the dominant cutting tools used on tunnel boring machines (TBM), as well as many other mechanical excavation units. One approach to estimate disc cutter wear life is to use Cerchar Abrasivity index (CAI). In this paper, the relationship between key rock properties including uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS), density (D) and brittleness index (BI) of rock and Cerchar abrasivity index (CAI) are evaluated. For this aim, 80 mechanized tunnel cases was examined and dataset was established, and then simple and multiple linear regression analysis were carried out to obtain the possible relations between CAI and relevant rock properties. It is found that each rock property mentioned herein have an influence on the CAI that is one of the main rock properties to estimate cutter wear life, however none of them by itself is not enough to estimate the CAI. So, the best equation was obtained via multiple regression analysis to estimate CAI as a function of BTS, D and BI of rock with correlation coefficient of r=0.81. The limited study shows that while CAI is one of the good indicators to estimate the cutter wear, rock properties including UCS, BTS, D and BI also have a great influence on disc cutter wear.