beta-beta aEuro(3)-Al2O3 precursor powder was successfully prepared by a solid-phase sintering method with Li2CO3, Na2CO3 (as the sources of Li2O and Na2O, respectively) and alpha-Al2O3 powder as the raw materials. The precursor was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results indicate that the amount of Na2O in the raw materials has a great effect on the formation of beta aEuro(3)-Al2O3 in the beta-beta aEuro(3)-Al2O3 precursor. When Na2O content is 10 wt%, the content of beta aEuro(3)-Al2O3 phase reaches the maximum value of 86.24 wt% in the precursor. The beta-beta aEuro(3)-Al2O3 ceramic was prepared from beta-beta aEuro(3)-Al2O3 precursor powder by isostatic pressing and burying sintering process. The conductive property of the beta-beta aEuro(3)-Al2O3 ceramic was examined by electrochemical impedance spectroscopy (EIS) method, and the density was measured by the Archimedes method. The results reveal that when 10 wt% Na2O was added, the sample exhibits the best performance with the lowest resistivity of 4.51 Omega center dot cm and the highest density of 3.25 g center dot cm(-3). A solid electrolyte battery of Pt|SnO2, Na2SnO3|beta-beta aEuro(3)-Al2O3|NaCrO2, Cr2O3|Pt was assembled by the beta-beta aEuro(3)-Al2O3 electrolyte tube to measure the open potential of the resulting battery, and the formation free energy of sodium stannate was calculated. In the temperature range of 1273-773 K, the relationship between formation free energy of sodium stannate and temperature was generated as follows: .