Grinding the mixture of kaolin and hydrazine concentrate can not only raise the speed of intercalation so that the intercalation rate reaches 96% in 10 minutes, but also greatly improve the refining of kaolin. When the complexes are heated to 120℃, the gas they send out can further delaminate kaolin. In this way, we can get the refined kaolin whose grain size is -2μm>90%, and the lamellar crystal is perfect. This technology offers an innovational thinking and a method for preparing double 90" refined kaolin.