Abstract: In order to strengthen the island foundation soil with microbially induced carbonate precipitation （MICP） technology， in our report， the sand column formed by mixing coral sand and coastal silty fine sand was used as the research object， the mixed sand specimen were prepared based on the microbial culture conditions， such as pH， temperature， and the concentration of cementing fluid handling； the effects of the different silty fine sand content on the compressive strength and local inhomogeneity of the samples were compared. The results showed that MICP technology is suitable for the treatment of mixed sand samples； the higher the fine sand content， the lower the compressive strength of the sample， however， too low dosage cause brittle failure of the specimen， which suggested that the unconfined compressive strength of the sample can be effectively improved and the overall cementing property of the sample will be good when the mixing content is between 16% and 20%.