The　fractional　frequency　transmission　system　(FFTS)　can　multiply　increase　transmission　capacity　by　using　a　lower　frequency　to　reduce　the　reactance　of　the　AC　transmission　system.　The　modular　multi-level　matric　converter　(M3C)　as　the　new　generation　of　the　AC/AC　converter　is　the　critical　equipment　of　FFTS.　The　self-start　control　strategy　for　M3C-based　FFTS　is　proposed　and　the　whole　start-up　procedure　is　divided　into　the　uncontrollable　stage　and　controllable　stage.　The　model　of　the　equivalent　circuit　in　an　uncontrollable　stage　is　built　and　the　mathematical　relation　between　the　maximum　charging　current　and　the　current-limit　resistor　is　obtained.　Finally,　a　digital　simulation　system　of　M3C-based　FFTS　is　established,　and　the　effectiveness　of　the　proposed　control　strategies　is　verified　by　simulation　results.　©　2019　Institution　of　Engineering　and　Technology.All　right　reserved.