Microbially induced carbonate precipitation (MICP) reinforcement technology, as a new environmentally friendly reinforcement method, has developed rapidly in recent years. The traditional MICP reinforcement method is limited to high reinforcement cost, poor environmental adaptability of exogenous mineralizing bacteria, and the potential environmental risks associated with the introduction of exogenous bacteria. The biostimulated MICP method using local urease bacteria contained in soil can effectively reduce the cost of reinforcement. In this paper, the biostimulated MICP method is used to reinforce the soil, and large-scale triaxial consolidation drained shear tests were carried out on the biotreated specimens before and after biostimulated MICP treatment to compare and analyze the shear characteristics of the treated and untreated specimens. Moreover, the distribution of calcium carbonate and the microscopic mechanism in the biotreated soil specimen were also investigated. The results show that the biostimulated MICP treatment primarily generates rhombohedral-shaped calcium carbonates, which are deposited in the soil, leading to a significant increase in strength and stiffness, as well as a significant reduction in volumetric strain. The distribution of calcium carbonate in soil specimen decreases with the increase of specimen depth, which leads to the shear failure at the bottom of specimen.