The kaolin deposits in Suzhou consist mainly of kaolinite, 7 halloysite and 10 halloysite, with less sericite and montmorillonite and varying amounts of alunite, gibbsite and phosphate minerals in company. On the whole, kaolinite and 7 halloysite are dominant in the upper part of the orebody and 10 halloysite in the middle and lower parts.Montmorillonite, gibbsite and secondary leaching type alunite are frequently seen near the bottom, together with localized phosphate minerals. The chemical compositions of kaolin minerals are approximately equal to theoretical values and SiO2/Al2O3 ratio of the major ore is close to 2.These mineral associations are products of different geological processes in different periods. After their formation, the kaolin minerals are only in temporary equilibrium with the surrounding environment and are thus in a relatively stable structural state. With the variation in surrounding geochemical environment, these minerals will change their stable structures gradually into unstable structures to reach new equilibrium. The conversion mainly includes (1)the transformation of halloysite into kaolinite, (2)the formation of secondary leaching type 10 halloysite, (3)the mutual conversion between halloysite and gibbsite and (4)the formation of Ca-montmorillonite. Based on the above discussion, the author has established a formation and evolution sequence for kaolin deposits and dealt tentatively with the relationship between the mineral evolution and the transformation of orebodies.