The protonic ceramic fuel cell (PCFC) is limited in performance by the delayed oxygen reaction on the cathode caused by low temperature. Herein, we investigate Ba0.9Co0.7Fe0.2Nb0.1O3-δ (BCFN), a cathode material with excellent electrocatalytic activity and structural stability. The electrical conductivity relaxation method was explored for the proton transport ability of BCFN material, which revealed a proton diffusion coefficient of 0.515 × 10−3 cm s−1 at 600 °C. To further enhance the proton conductivity of material and increase the reaction sites, a BCFN-BaCe0.7Zr0.1Y0.1Yb0.1O3−δ (BCZYYb) composite cathode was developed and its average thermal expansion coefficient value was lowered to 15.7 × 10−6 K−1 from 30 to 800 °C. At 700 °C, a single cell with a BCFN-BCZYYb cathode achieves a peak power density of 859 mW cm−2, and the Rp value is 0.05 Ω cm2. Furthermore, good durability of stable operation at 150 mA cm−2 for 100 h is obtained at 600 °C. These results imply that BCFN-BCZYYb could be an effective PCFC cathode.