The　geometric　and　electronic　structures　of　clean　TiC(001)　surface　were　investigated　using　first　principles　calculations　based　on　generalized　gradient　approximation　density　functional　theory.　The　structural　optimization　of　the　surface　shows　that　the　C　and　Ti　atoms　on　the　top　layer　move　outward　and　inward,　respectively.　The　results　of　the　band　structure　calculation　indicate　that　the　＂active＂　surface　states　of　TiC(001)　surface　located　around　2.3　eV　below　Fermi　level　are　originated　from　2p(z)　orbital　of　surface　C　atoms.　Furthermore,　the　influence　of　the　surface　relaxation　on　the　electronic　structures,　including　the　charge　densities,　work　functions　and　surface　core　level　shifts　are　also　discussed　in　the　paper.