Abstract: The firing temperature of early pottery from Nanzhuangtou site in Xushui, Hebei province, which is an important early Neolithic site in north China, was systematically analyzed through simulation experiments and measurement by dilatometer and XRD. The whole analysis results provide scientific proof for the open firing process. Simulation experiments make sure that the dilatometer is able to detect the expansion changes in low temperature. The high temperature reheating process with dilatometer analysis indicate that the firing temperature are little higher than 900℃ for one sample and lower than 900℃ for other five samples with firing temperature ranges of 550~650℃, 650~750℃ and 750~900℃. The results from mineral composition analysis of the samples by X-ray diffraction provide further evidence of the reliability of the thermal expansion measurement. From these experiments, the conclusion that the firing temperature of the samples is low and uneven could be obtained, which is consistent with that in ethnology report about open firing. So it seems that our ancestor in Nanzhuangtou used open firing process to make pottery at that time.