(Sm1−xYbx)2Zr2O7 (x=0, 0.5, 1.0) powders synthesized by chemical-coprecipitation and calcination method were pressureless-sintered at 1700°C for 10 h in air. Molten V2O5 reacts with (Sm1−xYbx)2Zr2O7 to form m-ZrO2 and rare-earth vanadates at 800°C. The thickness of corrosion scales was investigated to evaluate the hot corrosion resistance of (Sm1−xYbx)2Zr2O7. The hot corrosion resistance of (Sm1−xYbx)2Zr2O7 against molten V2O5 increases with increasing Yb content. The hot corrosion mechanisms were proposed based on phase diagrams and the difference in hot corrosion resistance was discussed on terms of basicity of (Sm1−xYbx)2Zr2O7 ceramics.