A new proton conducting Ba 0.95 K 0.05 Ce 0.6 Zr 0.2 Gd 0.16 Zn 0.04 O 3−δ electrolyte membrane was prepared on NiO-based anode support by suspension spray followed by a co-sintering at 1400°C for 4h. Chemical stability test shows that this new proton conductor displays adequate chemical stability against CO 2 at intermediate temperatures. The conductivity of Ba 0.95 K 0.05 Ce 0.6 Zr 0.2 Gd 0.16 Zn 0.04 O 3−δ in humidified H 2 is about 50% higher than that of BaCe 0.6 Zr 0.2 Gd 0.16 Zn 0.04 O 3−δ from 500 to 800°C. With La 0.8 Sr 0.2 MnO 3−δ cathode, fuel cell with Ba 0.95 K 0.05 Ce 0.6 Zr 0.2 Gd 0.16 Zn 0.04 O 3−δ electrolyte shows 1.02V of OCV and 354mW/cm 2 of maximum power density at 700°C, respectively. And the cell performance did not degrade after running at least for 10h.