Direct　ammonia　solid　oxide　fuel　cell　(DA-SOFC)　is　a　promising　device　to　realize　high-efficiency　NH3-to-power.　In　this　study,　we　fabricate　a　series　of　cobalt-based　spinet　ACo(2)O(4)　(ACO,　A　=　Zn,　Fe,　Ni)　oxide　as　DA-SOFC　cathodes　using　the　citric　acid　complexing　method.　We　prepare　three　cobalt-based　spine]　oxides　with　different　A-site　elements,　i.e.,　Zn,　Fe,　and　Ni,　to　establish　the　relationships　between　the　valence　and　active　site　of　ACO　spinel　oxide.　The　structural　analysis　based　on　XRD,　XPS,　TEC,　and　UV-Vis　diffuse　reflectance　confirms　that　NCO　exhibits　smaller　band　gap,　higher　electronic　conductivity,　and　better　compatibility　with　electrolyte.　The　electrochemical　results　indicate　that　the　cathodic　surface　of　NCO　containing　rich　Co3+　and　O-ads　leads　to　better　oxygen　reduction　reaction　(ORR)　activity.　The　maximum　power　density　of　the　DA-SOFC　using　NCO　cathode　reaches　1.06　W.cm(-2)　at　800　degrees　C,　superior　to　those　of　using　ZCO　(0.83　W.cm(-2))　or　FCO　(0.92　W.cm(-2))　cathode.　Kinetic　analysis　based　on　the　distribution　of　relaxation　time　(DRT)　and　electrochemical　impedance　spectroscopy　(EIS)　indicates　O-TPB　-　e(-)　＜-＞　O-TPB(-),　is　rate-　limiting.