Abstract: Research on microbial induced carbonate precipitation(MICP)is mainly aimed at sandy soil with large particle size,and MICP-treated silt needs further study.Therefore,a series of unconfined compressive strength tests were conducted to study strength change laws of marine silt treated by MICP.Ratios of bacterial solution and reinforcement solution,reinforcement solution concentration and different calcium sources were considered in the process of reinforcement and then were compared with unreinforced samples.The result showed that:(1) Mixing method could be used to strengthen the silty soil easily and evenly.With the improvement of treated effect,the samples gradually showed obvious brittleness.(2) The reinforcement solution concentration had the most significant effect on the unconfined compressive strength of the treated silty soil samples,and when it came to 1.5 mol/L,the unconfined compressive strength of the solidified soil samples could reach 1.5 times that of the unconsolidated samples.(3) The unconfined compressive strength of the samples treated by two calcium sources were similar but the values were different.(4) When the calcium source was CaCl2,and the volume ratio between bacterial solution and reinforcement solution in the mixing process was 3/7,and the concentration of reinforcement solution was 1.5 mol/L,the treatment effect of silty soil samples reached the best.