There　is　intensive　searching　for　superhard　materials　in　both　theoretical　and　experimental　studies.　Refractory　and　transition　metal　carbides　are　typical　materials　with　high　hardness.　In　this　study,　first-principles　calculations　were　performed　first　to　analyze　the　electronic　structures　and　mechanical　properties　of　the　tungsten-carbide-based　compounds.　The　results　indicated　that　tungsten　carbide　could　be　hardened　by　alloying　elements　with　high　work　functions　to　tailor　the　Fermi　level　and　electron　density.　Guided　by　the　calculations,　a　new　type　of　tungsten　carbide　alloyed　with　Re　was　synthesized.　The　Young＇s　modulus　and　hardness　of　the　Re-alloyed　tungsten　carbide　are　increased　by　31%　and　44%,　respectively,　as　compared　with　those　of　tungsten　carbide.　This　study　provides　a　new　methodology　to　design　superhard　materials　on　a　feasible　electronic　base　using　work　function　as　a　simple　guiding　parameter.