In order to explore the change of mechanical characteristics of surrounding rock of circular cavern under different confining pressures, biaxial compression tests were carried out on the rock-like materials containing circular caverns. The digital image technology was used to record the whole field strain evolution process, and the particle flow model was established according to the test to explore the influence of confining pressure on the compressive strength of surrounding rock of cavern and the development of cracks. The results showed : The size effect has a great influence on the mechanical characteristics of the model, and the peak compressive strength of the circular cavity model decreases with the increase of the cavity size. When the confining pressure increases, the compressive shear effect increases, and the failure mode of the cavern model changes from tensile strain to tensile shear composite failure. With the increase of confining pressure, the strain concentration area of circular cavity transfers from the upper and lower sides of the hole. When the confining pressure increases gradually, the tension is inhibited, the damage on both sides of the hole increases gradually, and the shrinkage deformation increases gradually. Finally, the mechanical variation characteristics of surrounding rock of circular cavern under different confining pressures are verified by numerical simulation.