The effect of Zn contents on the microstructure, structural stability and electrical property of BaSn0.5Y0.5−xZnxO2.75−δ (x=0–0.04, BSYZ) were investigated. The small amount of Zn doping (≥2mol%) can remarkably decrease the sintering temperature (1350°C) to obtain the dense pellets, and improve the structural stability under wet atmosphere. Zn doping is also favorable to promote the grain growth. The conductivities of samples are strongly dependent on the Zn contents, such as the total and grain boundary conductivities increase with the increase of Zn contents, but the bulk conductivity decreases. The bulk conductivity of BaSn0.5Y0.48Zn0.02O2.75−δ is 1.41×10−3S/cm2 at 600°C under wet Ar.