The accurate acquisition of rock hardness index during tunnel construction is a practical problem faced by rapid classification of tunnel surrounding rock. The current code requires that uniaxial saturated compressive strength of rock be used as the quantitative index of rock hardness. To find the best alternative scheme for uniaxial saturated compressive strength of rock, The advantages and disadvantages of different alternatives and indices of uniaxial saturated compressive strength of rock are analyzed and compared, and laboratory experimental analysis on rocks with different lithologies is conducted using Leeb hardness tester, and the relationship between Leeb hardness value and uniaxial saturated compressive strength of mudstone rock and sandstone rock is studied. The regression analysis of Leeb hardness and uniaxial saturated compressive strength of rocks is carried out using mathematical statistical software SPSS24.0. It points out that there is a strong correlation between Leeb hardness and uniaxial saturated compressive strength of rocks, and the regression prediction equation of uniaxial compressive strength and Leeb hardness value of rocks with different lithologies in saturated state is constructed.