From the view point of the electrode for SOFC, we studied the reactivity at the interface between La(1-x)A(x)MnO(3-z)(A=Ca and Sr) and YSZ (8 mol% Y2O3 doped zirconia) or La(0.8)A(0.2)CrO(3). The atomic diffusion and reaction at the boundaries were observed by SEM with EDX. The long term annealing of Ca substituted perovskite system at 1200 degrees C brought the formation of Ca-rich phase at the boundary, while no extra phase was found in the case of Sr substituted system.