Fe-based double perovskites represent a significant category of cobalt-free materials and exhibit promise as cathodes for solid oxide fuel cells (SOFCs) because of their lower thermal expansivity and reduced cost. However, they often encounter challenges associated with poor oxygen reduction reactivity stemming from intrinsic low electronic and oxygen-ion conductivity. In this investigation, Ca was introduced as a dopant for the first time to improve the electrochemical properties of PrBaFe2O5+δ (PBFO). The findings unveiled effective adjustments in the formation of oxygen vacancy by introducing Ca into PBFO. Therefore, the oxygen adsorption, dissociation, and charge transfer processes were modulated considerably. At 800 °C, PrBa0.9Ca0.1Fe2O5+δ (PBCFO) exhibited a Rp of 0.027 Ω cm2, representing a 78.1% reduction in comparison with PBFO. Concurrently, the output power density of the PBCFO increased by 17.3%. These results underscore the potential of Ca doping to elevate the ORR kinetics and CO2 tolerance of PBFO.