©　2016,　The　editorial　office　of　Transaction　of　China　Electrotechnical　Society.　All　right　reserved.　Triangular　carrier　pulse　width　modulation　(TCPWM)　method　and　the　space　vector　pulse　width　modulation　(SVPWM)　method　are　the　two　main　control　methods　used　in　cascaded　H　bridge　multilevel　converter.　There　is　a　certain　relationship　between　this　two　modulation　strategies,　but　this　relationship　has　not　been　well　studied　so　far.　Thus,　this　paper　studies　the　multi-level　SVPWM　modulation　sequence　and　TCPWM　unity.　By　superimposing　zero-sequence　onto　TCPWM　modulation　wave,　the　same　effect　with　the　SVPWM　modulation　is　achieved.　At　last,　this　paper　deduces　the　unity　of　the　SVPWM　and　TCPWM　in　n　level　with　arbitrary　number　of　segment　sequences.　Simulation　and　experimental　results　verify　the　correctness　of　the　unified　theory.