This paper presents the results of investigation on crystal, firing temperature and trace elements analysis of fragments 4~8 centriesexcavated from Kyong ju historical sites such as Wang kyong,Walsung, Hwangnam great tomb by application of optical microscope, neutron activation analysis and X-ray diffraction. Temper analysis of clay for identification of local or foreign production; Trace elements is not presented a unique chemical composition. That’s data have to be treated a statistical process in order to normalize. The results followed ;(1) Firing temperature could be estimated $700^{circ}C$ on some softness pottery at Walsung and most of hardness others are $1,000^{circ}C$ to $1,200^{circ}C$.(2) Crystal structures are divided into three kinds of mineralogical composition(Quartz, Mullite, Feldspar).(3) Considering of the results of statistical data, chemical composition of Walsung is more similarly Wang kyong than Hwangnam great tomb.