To　improve　the　yield　strength　of　an　FeCoCrNiMn　high-entropy　alloy　(HEA),　elemental　Ti　and　C　were　doped　into　the　alloy.　Subsequently,　an　in　situ　synthesized　carbides　particle-strengthened　HEA　matrix　composite　was　prepared　by　mechanical　alloying　(MA),　followed　by　a　vacuum　hot-pressing　sintering　(VHPS)　method.　The　TiC　nanoparticles　were　distributed　along　the　grain　boundaries.　The　microstructure　of　the　alloy　contained　a　face　centered　cubic　(FCC)　solid　solution　as　the　matrix　phase　and　small　amounts　of　TiC,　M23C6　and　M7C3　(where　M　=　Cr,　Mn,　Fe)　carbides,　The　addition　of　elemental　Ti　and　C　significantly　improved　the　room-temperature　compressive　yield　strength　of　the　FeCoCrNiMn　HEA　from　774　MPa　to　1445　MPa　(an　86.7%　increase),　accompanied　by　a　decrease　in　the　compressive　strength　and　plasticity.　Grain　boundary　strengthening　and　precipitation　strengthening　are　the　main　strengthening　mechanisms　of　the　alloy　doping　with　elemental　Ti　and　C.