Kaolinite-formamide intercalation compound was prepared by solution intercalation method. The intercalation ratio(I.R.) was evaluated based on the ratio of II /(II+IK).The influence factors on intercalation efficiency such as the type and contents of solvent, the temperature of intercalation reaction and the particle size of kaolinite sample were studied. The results shown that the highest intercalation ratio was 96% under room temperature. The formamide solution with vol.9% of water, methanol or ethanol is propitious to intercalation. The kaolinite sample with particle size more than 1.5μm, high purity and good dispersion in solution, is adequate for preparation high I.R. intercalation compound.