Using　the　density　function　theory　method　based　on　the　first　principle,　the　electronic　structures　of　TiC　solid　with　the　NaCl,　WC　and　CsCl　phases　have　been　investigated.　The　calculated　results　indicate　that,　at　the　zero　pressure,　the　order　of　relative　stability　for　the　three　phases　is　NaCl　phase＞WC　phase＞　CsCl　phase,　and　this　order　can　be　explained　by　comparing　the　electronic　states　near　the　Fermi　level.　As　the　pressure　increases,　the　CsCl　phase　is　to　be　stable　and　the　structural　phase　transitions　from　NaCl　phase　to　CsCl　phase　occurs　at　about　475.9　GPa.　The　transition　from　CsCl　phase　to　WC　phase　needs　more　higher　pressure.　Furthermore,　the　pressure-induced　influences　on　the　band　structures,　chemical　bonding　and　charge　densities　of　the　three　phases　are　also　discussed.