Based on the meshless method, the self-developed program is proposed to analyze the rock mechanics. In the present program, the Mohr-Coulomb criterion is adopted and the softening of material after plastic yield can be considered. The deformation of defective rock under uniaxial compression can be analyzed; and the evolution of deformation localization in defective rock can also be clarified. The calculation results show that the process of destruction of rock specimen is evolutionary. The material destruction and acoustic emission occurs at the defective weak particle of rock specimen with the loading process. A localized deformation zone produced with the crack expanding. A distinct shear failure zone formed in the rock specimen with the expansion and development of localized deformation zone. Defective particles played a control role in the specimen damage process. Rock acoustic emission records the plastic failure process of rock materials. The development of shear failure zone and plastic zone of rock specimen has a very similar way. However, the plastic area is greater than the shear failure zone; and the shear failure zone is located in the plastic zone. It can be concluded that the localized deformation occurs before the stress-loading step (strain) reaches the point of peak strength.