The　microstructure　and　oxidation　kinetics　of　Fe-B-based　alloys　at　927　K　in　air　with　different　boron　concentrations　of　0.95,　1.45,　2.10,　and　3.08　wt%　were　studied.　The　alloy　microstructures　were　interpreted　to　consist　of　alpha-Fe,　Fe2B,　and　pearlite.　After　100-h　oxidation,　the　oxides　comprised　Fe2O3　at　the　surfaces　and　a　mixed　B2O3-SiO2　layer　at　matrix/oxide　interface.　The　formation　of　mixed　oxides　layer　was　affected　by　boron　content　in　the　alloy　and　had　obvious　influence　on　the　oxide　morphology.　The　isothermal　oxidation　kinetics　at　973　K　exhibited　initial　rapid　mass　loss　followed　by　slow　mass　loss,　and　the　oxidation　rate　constants　of　the　two　oxidation　stages　demonstrated　completely　opposite　tendencies　with　the　increase　of　boron.　The　Fe-B　3.08　wt%　alloy　exhibited　the　best　oxidation　resistance　after　100　h　of　cyclic　oxidation　due　to　the　formation　of　a　well-distributed　and　continuous　B2O3-SiO2　mixed　oxide　layer.