The　marine　controlled　source　electromagnetic　transmitting　method　could　greatly　improve　the　success　rate　of　the　offshore　drilling　and　reduce　drilling　risk　greatly.　So　it　has　been　widely　used　in　the　abroad　exploration　industry　of　marine　oil　and　gas　in　recent　years.　As　a　primary　means　of　subsea　communications,　power　line　communication　(PLC)　system　plays　a　major　role　in　the　marine　electromagnetic　exploration　system.　The　communications　platform　of　marine　controlled　source　electromagnetic　transmission　system　has　been　built　by　PLC　system　and　the　LabVIEW　software　in　this　paper.　The　GPS　module　has　been　used　for　time　synchronization　in　this　platform.　The　communication　between　the　deck　control　platform　and　subsea　uses　the　PLC　system.　And　marine　transmitter　control　platform　could　timely　display　and　save　the　information　of　the　operating,　operating　current　and　operating　frequency　in　the　subsea　system.　The　experiment　results　verify　that　this　platform　could　work　stably　for　a　long　time　and　have　the　high　transmission　rate　about　1kb　/　s.