Due to high emissions, energy consumption and pollution of the traditional Portland cement, a novel cementitious material-bio-calcite cement, was necessary to be developed.The calcite crystals, induced by ureolytic bacteria, could form bridges between loose particles and cemented them together.In this paper, a series of sand-cemented experiments were conducted to confirm the cemented properties and the evolution law of microstructure was revealed by X-ray computed tomography (X-CT) technique.To further analyze the bio-grout process and predict the performance of the microbe cementitious material, a numerical model based on the concentration of bacteria is established.Moreover, special attention was paid to explore the essence of cementation mechanism, and the results that the C-O bond of calcite, Si-O bond and Si atomic binding energy analysis showed that microbial induced calcite under the action of organic matrix secreted by microorganisms interacted with surface of loose particles to form.the interrnolecular hydrogen bond.Some potential applications of the bio-cement for treatment of sandy soil foundation, suppress dust emission and remediation of heavy metals in contaminated soil etc.are discussed.