Microbiologically Induced Calcite Precipitation (MICP) has been proposed to improve the weak sandy soil ground via bio-augmentation or bio-stimulation. Compared with bio-augmentation, bio-stimulation approach has more advantages since indigenous microbes are more likely to survive and effectively generate MICP. This paper reports a preliminary experimental study of investigating the mechanism of bio-stimulation and shear strength behavior of bio-cemented carbonate sand via a series of column enrichment and soil direct shear tests. The carbonate sand was firstly treated by enrichment media containing nutrient solution and urea, and then treated by cementation solution containing urea and calcium chloride. After treatment, direct shear tests were conducted under four normal stress (25 kPa, 50 kPa, 100 kPa and 200 kPa). The results indicate that indigenous ureolytic bacteria can be enriched in soil effectively, and the shear strength can be improved significantly.