The　equilibrium　phases　of　high-boron　high-speed　steel　whose　compositions　are　0-3.0%　B,　0.2-0.8%　C,　4.0-8.0%　Cr,　2.0-4.0%　Mo,　0.5-1.5%　Al,　0.5-1.5%　Si,　0-1.0%　Mn,　and　0.5-1.5%　V　were　calculated　and　vertical　section　pseudo-binary　phase　diagrams　were　drawn　by　Thermo-Calc　software.　The　phase　transformation　and　carbides　precipitation　temperatures　were　measured　by　using　differential　scanning　calorimetry.　The　type　of　carbides　and　matrix　of　the　as-cast　specimens　were　determined　by　using　x-ray　diffraction.　Meanwhile,　the　shape　and　the　number　of　carbides　in　the　different　specimens　were　detected　by　using　optical　microscope　and　scanning　electron　microscope.　The　influence　of　boron,　carbon,　aluminum,　and　chromium　elements　on　equilibrium　phase　diagrams　was　discussed.　The　calculation　results　obtained　from　Thermo-Calc　software　are　agreed　with　the　ones　from　experiments.　This　work　provides　a　practical　method　for　engineers　and　researchers　in　related　areas.