Abstract: Based on the indoor biaxial test of quartz sandstone, the numerical model of PFC^2D particle flow is established.Parallel bond contact is selected between the particles.According to the experimental results, the elastic modulus, Poisson’s ratio and peak stress are different for quartz sandstone samples under natural and saturated conditions.The meso-parametric calibration under confining pressure finally yields a stress-strain curve that is basically consistent with the laboratory test.The evolution law of mesoscopic parameters such as contact force, coordination number and porosity during loading was analyzed to explore the failure mechanism of quartz sandstone.The results show that the meso-parameter calibration of the biaxial compression test can ignore the influence of the shear strength indicators c and φ.Before and after the failure, the normal contact force and the tangential contact force existed between the particles in the statistical range of the sample in all directions.The presence of confining pressure affects the initial coordination number and porosity of the sample, and has little effect on the rate of change of coordination number and porosity.The results show that this numerical method is feasible in exploring the microstructural evolution characteristics of rock samples.