<p>Microbiologically induced calcite precipitation (MICP) is an environmentally friendly foundation-treatment method that can effectively improve the mechanical properties of soil after solidification. The macroscopic mechanical properties after MICP reinforcement are closely related to the particle shape of the sand body. The influence of particle shape parameters on the physical and mechanical properties of MICP-treated sand was explored. MICP- solidified sand was analyzed by optical microscopy and the influence of particle shape on the formation morphology and spatial distribution of calcium carbonate was determined. Scanning electron microscopy and unconfined compressive strength tests were conducted to respectively determine the amount of calcium carbonate produced and the macroscopic mechanical characteristic parameters of MICP-treated sand with different particle shapes. The experimental results show that the shape of the calcareous sand particles strongly influences the unconfined compressive strength of MICP after curing: when the shape of the particles is too round, it is difficult to generate calcium carbonate, which results in a reduction of the unconfined compressive strength and ultimately affects the MICP reinforcement effect. The smoother the surface of the calcareous sand particles, the more unfavorable this is to the attachment and precipitation of calcium carbonate crystals, and the weaker is the cementation effect produced between particles.</p>