Yb3+-doped Y2O3 and (Y0.9Sc0.1)2O3 transparent ceramics were fabricated, and their microstructures, structural and spectral properties were investigated. Sc2O3 can effeciviely inhibit the excessive grain growth in Yb:Y2O3 ceramics, and increased the transparency. The lattice parameter of Yb:(Y0.9Sc0.1)2O3 became small due to introducing of Sc3+ ions. The emission bands of Yb:(Y0.9Sc0.1)2O3 ceramics are inhomogeneously broadened compared to Yb:Y2O3. The broad emission bandwidths of Yb:(Y0.9Sc0.1)2O3 ceramics are favorable for the generation of ultrashort mode-locked pulse laser.