Abstract: Based on different shear failure modes in rock uniaxial compression tests, the relationship among the uniaxial compressive strength, cohesion and internal friction angle is deduced by using the limit analysis method. According to the uniaxial and triaxial test results of rock, the correctness of the formula for calculating the uniaxial compressive strength based on the M-C criterion parameters is verified. The difference between the results obtained from the formula and the experimental ones is between 6% and 10%. The cohesive force and internal friction angle of rock are calculated by combining the actual uniaxial shear failure modes of rock and the test results. The results show that the proposed method for calculating the cohesion and internal friction angle based on the mode of uniaxial shear failure and the value of uniaxial compressive strength is accurate and practical. The formula also reveals the internal relationship between failure modes of rock and parameters of rock mechanics.