At present, the push-rod thermal expansion method is most widely used in determining firing temperatures of ancient ceramics. Through review of the research status of this method and application to ancient Chinese pottery, white porcelain and black porcelain, we analyzed their thermal expansion curve characteristics in detail. In combination with simulation experiments on high-iron bodies, it was proposed that firing temperature analysis should be carried out from three types: low-temperature pottery (below 800 ℃), high temperature pottery (above 800 ℃) with obvious shrinkage turning points, and high temperature pottery with no shrinkage but only expansion turning points at high temperatures. Using a tangent line to calculate the firing temperature has higher accuracy only in the case of shrinkage turning points, and the temperatures of expansion turning points can be used only as references. At the same time, the characteristics of raw materials should be studied from the aspect of chemical composition using a relatively complete sintering step curve and verified by combining physical performance indexes such as water absorption rate and the like. These results provide a reference for further applications of this method.