To　improve　thermal　barrier　applications　in　advanced　vehicle　engines,　a　novel　Fe-based　amorphous　composite　coating　was　designed　by　introducing　ceramic　oxides　and　was　prepared　by　atmospheric　plasma　spraying　(APS).　The　microstructure　and　related　properties　of　the　as-deposited　coating　were　investigated　in　detail.　The　composite　coating　comprises　a　well-formed　FeCrNbBSi　amorphous　metallic　matrix　and　dispersed　yttria-stabilized　zirconia　(YSZ)　splats.　A　unique　Si-oxide　interfacial　layer　with　a　thickness　of　several　nanometers　and　an　amorphous　structure　forms　between　the　metallic　matrix　and　ceramic　phase,　which　is　attributed　to　a　combination　of　multiple　effects.　The　composite　coating　displays　extremely　low　thermal　conductivity　from　2.28　W/mK　at　100　°C　to　3.36　W/mK　at　600　°C　and　can　increase　the　surface　temperature　of　the　piston　crown　by　18.93　°C,　which　implies　a　significant　means　of　enhancing　the　power　efficiency.　The　improved　thermal　barrier　ability　of　the　composite　coating　is　revealed　as　the　crucial　effect　of　the　Si-oxide　interfacial　layer,　which　induces　an　increased　interfacial　thermal　resistance.　The　fracture　toughness　of　the　composite　coating　remains　at　3.40　MPa·m1/2,　comparable　to　that　of　the　monolithic　amorphous　coating,　3.74　MPa·m1/2,　which　is　closely　related　to　the　formation　of　a　Si-oxide　layer　and　its　nanoscale　thickness.　Therefore,　the　Fe-based　amorphous　composite　coating　developed　here　demonstrates　great　potential　as　an　innovative　metal-based　thermal　barrier　coating　for　application　in　vehicle　engines　and　provides　specific　inspiration　for　future　works　exploring　the　interfacial　engineering　of　coating.