Abstract: To study the mechanical characteristics of yellow sandstone under different confining pressures, acoustic emission characteristics and rock fracture morphology, using ROCK 600-50 rock tri-axial rheological apparatus and acoustic emission system to carry out the conventional tri-axial test for yellow sandstone, to study the peak stress, peak strain, residual strength and mode of post-embedded of yellow sandstone in different confining pressures and discuss the evolution of acoustic emission counting in yellow-sandstone fracture process. The results show that: the peak stress, axial peak strain and residual strength of yellow sandstone specimens increase with the increase of confining pressure; the influence of confining pressure on radial peak strain is weaker; through the analysis of acoustic emission counting, yellow sandstone damage degree is more intense with the increase of confining pressure, and secondary or multiple failures may occur. Confining pressure reduces the number of yellow sandstone main cracks in the process of failure, and significantly inhibits the production of the secondary cracks.