Nano LSF (La_0.6Sr_0.4FeO_3-δ)-YSZ was prepared by infiltration process for both SOFC and SOEC modes. XRD pattern and SEM characterization had demonstrated that the nano-sized LSF perovskite particles were uniformly distributed onto the inner surface of the YSZ backbone. The electrochemical performances of the cell were evaluated for both power generation and steam electrolysis, during which humidified hydrogen gas and feed gas (50%H₂O+25%H₂+25%N₂) were introduced, respectively. Furthermore, the electrochemical stability of the cell employing the LSF-YSZ composite electrode was investigated at 0.5 A*cm^-2 and 0.8 A*cm^-2 for fuel cell and steam electrolysis operation, respectively. Subsequently, SEM images of the post-test cells had exhibited that the LSF-infiltrated YSZ electrodes had no obvious structural variation. The results indicated that the cell with nano-LSF-YSZ electrode had shown high long-term stability for both fuel cell and electrolysis conditions.