MoSi2　alloys　modified　with　and　without　1　at.　%　B　were　prepared　and　oxidized　at　1250　celcius　for　100　h.　The　B-modified　MoSi2　alloy　showed　a　significant　24.2　%　reduced　mass　gain　compared　with　the　MoSi2　alloy　without　B　modification.　Influence　of　the　minor　B　addition　on　the　oxidation　behavior　of　MoSi2　alloy　was　further　in-depth　investigated　with　First-principle　calculation.　The　results　indicate　that　the　added　B,　on　one　hand,　enhances　the　O　adsorption　capacity　and　diffusion　activation　energy　of　MoSi2　alloy,　on　the　other　hand,　facilitates　the　formation　and　stabilization　of　the　silica　scale　on　the　surface.