Solar　thermochemical　(STC)　technology　utilizes　the　entire　spectrum　of　solar　energy　to　decompose　water　to　produce　hydrogen.　This　technology　reduces　carbonic　fuels,　nearly　only　producing　hydrogen　rather　than　hydrogen-oxygen　mixture.　However,　low　water-splitting　activity　of　redox　materials　restricts　improvement　of　water-hydrogen　conversion　ratio　and　fuel　production　efficiency.　Recently,　a　kind　of　perovskite　LaFeO3　attracts　attention,　because　of　the　good　performance　in　photocatalysis　hydrogen　production.　Nevertheless,　how　LaFeO3　system　works　in　STC　water-splitting　cycle　is　rarely　studied.　In　this　paper,　the　first　principle　method　at　density　functional　theory　level　is　adopted　to　reveal　the　hydrogen　production　mechanism　of　perovskite　LaFeO3　doped　with　25%　Sr/Ca　at　A　site.　Hydrogen　migration　on　material　surface　determines　hydrogen　generation　rate.　The　activation　energy　of　25%-Ca-doped　LaFeO3　is　relatively　lower　150.09　kJ/mol.　In　addition,　fuel　production　efficiency　has　been　calculated.　When　water　to　hydrogen　conversion　ratio　is　100%,　solar-to-fuel　efficiency　can　reach　maximum　0.472.　The　effect　of　water-splitting　kinetics　on　hydrogen　production　is　also　discussed.　The　results　indicate　that　when　T-red　=　T-oxi　=　T　=　1200K　and　water　to　hydrogen　conversion　ratio　is　10%,　the　dynamic　efficiency　of　La0.75Ca0.25FeO3　can　reach　20%.　This　research　can　provide　index　for　improving　the　hydrogen　production　performance　of　STC　technology.　(C)　2020　Hydrogen　Energy　Publications　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.