The　in-depth　study　of　the　DC　voltage　balancing　of　the　star　connection　cascaded　H　bridge　multilevel　static　var　generator　(SVG)　has　been　made　in　this　paper.　And　the　control　system　with　three　layers　of　the　DC　voltage　balance　has　been　established.　The　first　layer　is　the　total　DC　side　voltage　control,　which　is　maintained　to　be　constant　through　generating　the　fundamental　positive　sequence　active　current.　The　second　layer　is　the　balancing　control　between　three　phases.　Through　the　injection　of　the　zero　sequence　voltage　into　the　command　voltage,　we　can　make　the　redistribution　of　the　three-phase　power,　so　as　to　realize　the　DC　voltage　balance　between　three　phases.　In　this　method,　through　feeding　forward　the　power　generated　by　the　grid　voltage　and　the　output　current,　the　rapid　dynamic　regulation　can　be　achieved.　The　third　layer　is　the　balancing　control　among　modules　in　each　phase.　Through　fine　tuning　the　command　voltage　of　each　module　in　each　phase　along　the　direction　of　the　current,　we　can　make　the　redistribution　of　the　power　absorbed　by　each　module,　so　as　to　ensure　that　the　DC　side　voltage　of　each　module　in　each　phase　is　equal　to　the　given　value.　Experimental　results　verify　the　correctness　and　reliability　of　the　proposed　control　method　in　the　end.　©　2016,　The　editorial　office　of　Transaction　of　China　Electrotechnical　Society.　All　right　reserved.