Abstract: Hydrogen energy has become an effective substitute for fossil energy due to its advantages of high efficiency, cleanliness and renewability. Reversible solid oxide cell (RSOC) can use hydrogen to output electricity or electrolyze H₂O to produce hydrogen, which has very important research significance. The performance optimization of La_0.65Sr_0.35MnO₃ (LSM) oxygen electrode was studied in this research. Sm_0.2Ce_0.8O_1.9 (SDC) and Sm_0.5Sr_0.5CoO_3−δ (SSC) nanoparticles were introduced into the LSM oxygen electrode. The polarization resistance of the one-time alternate LSM-SDC-SSC1 oxygen electrode at 800°C is 0.49 Ω·cm², which is 43% of the LSM oxygen electrode. The effect of infiltration sequence of SDC and SSC on the morphology and properties of the electrode decrease with the increase of impregnation time. The two-time alternate LSM-SDC-SSC2 oxygen electrode show the lowest polarization overpotential and polarization resistance. The Ni-(Y₂O₃)_0.08(ZrO₂)_0.92 (YSZ)/YSZ/LSM-SDC-SSC2 single cell obtain a maximum power density of 870 mW·cm⁻² in solid oxide fuel cell (SOFC) mode and a maximum electrolysis current density of −1150 mA·cm⁻² in the solid oxide electrolytic cell (SOEC) mode at 800°C, which show good reversible cell performance.