The electrolyte of the proton conducting solid oxide fuel cell is the key component affecting both the performance and the stability. In this study, B-site cation-doped BaCe0.9M0.1O3-δ (BCM, M=Sc, Y, Zr, Nb) proton conducting ceramics are prepared via solid-state reaction approach. The effect of B-site doping on its sintering characteristics and mechanical properties are examined by material characterization and nanoindentation test. The results show that trivalent ion doping can promote the particle growth during sintering, while high-valent ion doping can inhibit the particle growth. In terms of mechanical properties, the Young’s modulus of the doped BCM decreases with the increase of the ionic radius of the trivalent doping elements (Sc and Y), and decreases with the increase of the valence state of the different valent doping elements (Y, Zr, and Nb).