Electronic　properties　of　rare-earth　orthoferrites,　RFeO3　(R　=　rare　earths)　with　optimized　perovskite-type　structures　have　been　investigated　systemically　using　the　first　principles　method　with　a　plane　wave　basis　set.　Ferromagnetic　(FM)　and　antiferromagnetic　(AFM)　structures　have　been　studied　according　to　the　different　arrangements　of　magnetic　moments　of　the　Fe　atoms.　The　results　indicate　that　the　AFM　phase　is　more　stable　than　the　FM　one　at　the　normal　temperature.　The　optimized　structures　of　AFM　phase　are　in　good　agreement　with　experiments.　In　both　the　FM　and　AFM　phases,　the　magnetic　moment　of　R　atom　is　the　same　as　that　of　the　free　R3+　ion.　For　the　Fe　atom,　the　magnetic　moment　in　the　FM　phase　is　smaller　than　in　the　AFM　one,　and　it　decreases　for　both　structures　with　increasing　atomic　number　of　R　atom.　For　a　given　phase,　the　band　structures　with　different　R　atoms　are　very　similar.　The　most　distinct　difference　between　the　band　structures　of　the　FM　and　AFM　phases　is　that,　a　band　gap　exists　at　the　Fermi　level　for　AFM　arrangement　but　not　for　the　FM　phase.