This paper studied the mineralogical characteristics of kaolin from Longyan by means of chemical analysis, mineral examination, SEM, XRD, IR and DTA-TG. It is shown that the content of Al2O3 and SiO2 is very close to the theoretical value, with tiny content of Fe and Ti. The content of K2O is higher because of residual mica. The results also show that Longyan kaolin is made up of kaolinite with minor mica and a very small amount of quartz, and its natural whiteness varies from 83% to 92%. The SEM photographs of Longyan kaolin show clear layer structure 0.1~5 μm in size, and a small amount of rod-shaped kaolinite. The results indicate that acetate ions insert between the inner layers of kaolinite under the participation of water, and different intensities and types of hydrogen bonds exist between acetate ions and the inner surface hydroxyl of kaolinite.