Buried glazed pots are apt to exhibit various sorts of damage due to impact of physical and chemical factors. Exfoliation of the glazed layers is one of the most common ones. This paper describes studies by microscopic observation, elemental analysis, thermal expansion coefficient analysis and water absorption tests of glaze exfoliation of Tang dynasty pots excavated from four archaeological sites in Shanxi and Henan provinces. The study shows that the glaze of Huangye kiln samples, in Gong County, is better preserved and shows little exfoliation compared with samples from three other archaeological sites, including the Huangbao kiln in Tongchuan city, the Liquanfang kiln in Xi’an city and the Tomb of the Yide Prince in Qian County; later specimens are severely exfoliated. Further research indicates that the essential causes of the glaze exfoliation are related to 1) the different thermal expansion coefficient rates of the body and glaze of the pottery and 2) the low degree of sintering of the pottery body.