The　effect　of　Si　on　the　microstructure　and　properties　of　hypereutectic　high-chromium　cast　iron　was　investigated.　The　results　show　that　Si　is　only　solid-dissolved　in　the　matrix,　and　the　content　of　Si　is　higher　in　the　matrix　near　the　edge　of　the　primary　carbide.　As　the　Si　content　increased　from　0.5　to　2.6%,　the　primary　carbides　in　hypereutectic　high-chromium　cast　iron　were　significantly　refined,　and　the　refining　mechanism　was　verified　by　first-principles　calculations.　The　increase　of　silicon　content　also　leads　to　the　increase　of　carbide　volume　fraction　from　52.4　to　63.9%,　the　decrease　of　austenite　volume　fraction　from　45.8　to　2.0%,　and　the　matrix　structure　gradually　transforms　from　gamma-Fe　to　alpha-Fe.　After　hypereutectic　high-chromium　cast　iron　was　quenched　at　1050　degrees　C,　a　large　amount　of　secondary　carbides　were　precipitated　in　the　matrix　and　the　precipitation　of　secondary　carbides　decreased　significantly　with　the　increase　of　silicon　content.　After　quenching　at　1050　degrees　C,　the　hardness　of　hypereutectic　high-chromium　cast　iron　increased　significantly,　but　the　hardness　of　high-silicon　(1.9Si　and　2.6Si)　samples　did　not　change　significantly.　Increasing　the　quenching　temperature　and　prolonging　the　holding　time　can　significantly　improve　the　hardness　of　high-silicon　samples.　The　increase　of　silicon　content　can　significantly　improve　the　wear　resistance　of　hypereutectic　high-chromium　cast　iron.　When　the　silicon　content　exceeds　1.9%,　the　wear　resistance　decreases.