In Fig. 6., the effect of sintering temperature and oxygen deficiency on the critical temperature was shown. The relation of these parameter was almost be the linear dependence so we can conclude that the critical temperature depends on the deficiency and sintering temperature. The higher deficiency is, the higher critical temperature become. Then, the highest deficiency, Y123, has the highest critical temperature. The ratio of Cu3+/Cu2+ versus c/a of all samples was shown in Fig. 7. We found that the ratio of Cu3+/Cu2+ depended on the sintering temperature. The Y123 has the maximum Cu3+/Cu2+ and the Y145 has minimum that agrees with the highest Tconset of Y123 and the lowest Tcoffset of Y145 (Fig. 5).