BaCe 1−x Ga x O 3−δ (x=0.1, 0.2) and BaCe 0.8 Y 0.2 O 3 (BCY) powders are successfully synthesized by a solid-state reaction method. According to thermal gravity analysis in the atmosphere of CO 2 , BaCe 0.9 Ga 0.1 O 3−δ (BCG10) and BaCe 0.8 Ga 0.2 O 3−δ (BCG20) are quite stable while BaCeO 3 shows obvious reaction and decomposes into CeO 2 and BaCO 3 . A fuel cell with electrolyte of BaCe 0.8 Ga 0.2 O 3−δ is prepared by a suspension spray combining with in situ sintering method and tested from 600 to 700°C with humidified hydrogen (∼3% H 2 O) as the fuel and the static air as the oxidant. An open-circuit potential of 0.99V and a maximum power density of 236mWcm −2 are obtained for the single cell with an interface resistance 0.32Ωcm 2 at 700°C.