Nanoscale　perovskite　oxides　with　enhanced　electrocatalytic　activities　have　been　widely　used　as　oxygen　electrodes　of　reversible　solid　oxide　cells　(RSOC).　Here,　La0.6Sr0.4FeO3-δ　(LSF)　nanoscale　powder　is　synthesized　via　a　novel　molten　salt　method　using　chlorides　as　the　reaction　medium　and　fired　at　850　°C　for　5　h　after　removing　the　additives.　A　direct　assembly　method　is　employed　to　fabricate　the　LSF　electrode　without　a　pre-sintering　process　at　high　temperature.　The　microstructure　characterization　ensures　that　the　direct　assembly　process　will　not　damage　the　porosity　of　LSF.　When　operating　as　a　solid　oxide　fuel　cell　(SOFC),　the　LSF　cell　exhibits　a　peak　power　density　of　1.36,　1.07　and　0.7　W/cm2　at　800,　750　and　700　°C,　respectively,　while　in　solid　oxide　electrolysis　cell　(SOEC)　mode,　the　electrolysis　current　density　reaches　1.52,　0.98　and　0.53　A/cm2　under　an　electrolysis　voltage　of　1.3　V,　respectively.　Thus,　it　indicates　that　the　molten　salt　routine　is　a　promising　method　for　the　synthesis　of　highly　active　perovskite　LSF　powders　for　directly　assembled　oxygen　electrodes　of　RSOC.　©　2020　by　the　authors.