The　spoolable　compliant　guide　(SCG)　maintains　S-shaped　dynamic　stability　in　the　marine　environment.　At　present,　limited　studies　have　been　reported　on　the　mechanical　laws　of　coiled　tubing　(CT)　injection　by　employing　SCG.　In　this　study,　an　experimental　platform　was　developed　to　simulate　the　CT　injection　process　in　SCG.　The　axial　force　transmission　characteristics,　buckling　laws,　and　contact　mechanism　of　the　CT　were　investigated.　The　results　showed　that　an　increase　in　the　diameter　of　the　inner　pipe　delayed　the　occurrence　of　sinusoidal　and　helical　buckling　and　improved　the　transmission　efficiency　by　13.0%.　An　increase　in　the　outer　pipe　diameter　showed　no　significant　effect　on　the　efficiency,　however,　it　increased　the　injection　length　of　the　inner　pipe　by　30.4%.　The　friction　force　increased　significantly　after　the　helical　buckling　of　the　inner　pipe.　Based　on　the　results,　the　pre-sented　research　is　beneficial　in　establishing　CT＇s　theoretical　framework　and　enhancing　operational　effectiveness.