To enhance the solidification effect of enzyme-induced calcium carbonate precipitation (EICP) technique, this study employed EICP combined with kaolin to treat standard sand for solidification. Two experimental variables were set: the amount of kaolin added and the curing time. Macroscopic and microscopic experiments were conducted on solidified sands under different variable combinations. The experimental results revealed that the unconfined compressive strength of the EICP-combined kaolin solidified sand continued to increase with the increase in kaolin content and curing time. The compressive strength after curing with 4% kaolin content for 14 days was 722.19 kPa, which was 13.15 times that of pure EICP solidified sand. The calcium carbonate precipitation rate did not continue to increase with curing time or kaolin content. The efficiency of calcium carbonate precipitation was highest when cured with 3% kaolin content for 7 days. As the kaolin content increased, the porosity first decreased and then increased, with the minimum porosity observed at a kaolin content of 2%. The pore structure of the solidified sand before and after adding kaolin changed from being dominated by medium pores (accounting for over 90%) to being dominated by small pores (around 80%), indicating a significant improvement in the pore structure. The calcium carbonate crystals deposited between the particles of the EICP-combined kaolin solidified sand were mainly aragonite spheres, which were stacked and filled in the interstices between sand particles and covered the surface of sand particles, significantly enhancing the bonding effect between sand particles.