Thin section petrography, differedtial thermal analysis, infrared spectroscopy,electronic microscopy and X-ray diffraction have been used in the study of pyrophyllite and pyrophylitites from Liyang, Jiangsu. The difference in meaning is known between the pyrophyllite and pyrophyllitite. Two kinds of pyro-Phyllite have been found from the pyrophyllitites in this area. It is clear thatthe previously so-called pyrophyllite is referred to"pyrophyllitite" indeed. A preliminary classification for pyrophyllitites has been made by the author.