β-β″-Al_2O_3 precursor powder was successfully prepared by a solid-phase sintering method with Li_2CO_3,Na_2CO_3 (as the sources of Li_2O and Na_2O, respectively) and α-Al_2O_3 powder as the raw materials. The precursor was characterized by X-ray diffraction (XRD) and scan-ning electron microscope (SEM). The results indicate that the amount of Na_2O in the raw materials has a great effect on the formation of β″-Al_2O_3 in the β-β″-Al_2O_3 precursor.When Na_2O content is 10 wt%,the content of β″-Al_2O_3 phase reaches the maximum value of 86.24 wt% in the precursor. The β-β〃-Al_2O_3 ceramic was prepared from β-β″-Al_2O_3 precursor powder by isostatic pressing and burying sintering process. The conductive property of the β-β″-Al_2O_3 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% Na_2O was added, the sample exhibits the best performance with the lowest resistivity of 4.51 Ω·cm and the highest density of 3.25 g·cm~(-3). A solid electrolyte battery of Pt|SnO_2, Na_2SnO_31|β-β″-Al_2O_3|Na-CrO_2, Cr_2O_3|Pt was assembled by the β-β″-Al_2O_3 elec-trolyte 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:ΔG_(Na_2SnO_3)~0= —1040.83 + 0.2221T± 7.54. β-β “-Al_2O_3 precursor powder was successfully prepared by a solid-phase sintering method with Li_2CO_3, Na_2CO_3 (as the sources of Li_2O and Na_2O, respectively) and α-Al_2O_3 powder as the raw materials. ray diffraction (XRD) and scan-ning electron microscope (SEM). The results indicate that the amount of Na_2O in the raw materials has a great effect on the formation of β ”-Al_2O_3 in the β-β“ -Al_2O_3 precursor.When Na_2O content is 10 wt%, the content of β ”-Al_2O_3 phase reaches the maximum value of 86.24 wt% in the precursor. The β-β“ -Al_2O_3 ceramic was prepared from β-β ”-Al_2O_3 precursor powder by isostatic pressing and The conductive property of the β-β “-Al_2O_3 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% Na_2O was added, the sample exhibits the best performance with th A was found to have the lowest resistivity of 4.51 Ω · cm and the highest density of 3.25 g · cm -3. A solid electrolyte battery of Pt | SnO_2, Na_2SnO_31 | β-β ”-Al_2O_3 | Na-CrO_2, Cr_2O_3 | Pt was assembled by the β-β "-Al_2O_3 elec-trolyte 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: ΔG_ (Na_2SnO_3) ~ 0 = -1040.83 + 0.2221T ± 7.54.