Abstract: Due to change of stress in rock mass during excavation, brittle failure will happen in hard rock engineering with high in-situ stress, such as spalling, rock burst, etc., and the in-situ stress along tunnel axis with linear underground engineering is influenced by various factors. It is important to determine the distribution of in-situ stress for safe construction and lining support design. Based on the introduction of statistical distribution of in-situ stress, stress redistribution and deviatoric stress law of the surrounding rock are simulated under different combinations of tunnels and directions of the principal stress. Based on the failure criterion for brittle rock, a formula for solving the in-situ stress of plane perpendicular to tunnel axis is deduced considering the characteristics of failure of hard rock brittle. The formula is verified by practical engineering with high coherency. The results provide references for the determination of in-situ stress of underground engineering and the design of engineering support.