In　this　work,　a　novel　intumescent　flame　retardant　(IFR)　system　was　fabricated　by　the　introduction　of　chitin　as　a　green　charring　agent,　ammonium　polyphosphate　(APP)　as　the　acid　source,　and　melamine　(MEL)　as　the　gas　source.　The　obtained　chitin-based　IFR　was　then　incorporated　into　a　polylactic　acid　(PLA)　matrix　using　melt　compounding.　The　fire　resistance　of　PLA/chitin　composites　was　investigated　via　the　limiting　oxygen　index　(LOI),　UL-94　vertical　burning,　and　cone　calorimeter　(CONE)　tests.　The　results　demonstrated　that　the　combination　of　10%APP,　5%chitin　and　5%MEL　could　result　in　a　26.0%　LOI,　a　V-0　rating　after　UL　and　a　51.2%　reduction　in　the　peak　heat　release　rate　during　the　CONE　test.　Based　on　the　mechanism　analysis　from　both　the　morphology　and　the　chemical　structure　of　the　char,　it　was　suggested　that　chitin　was　a　promising　candidate　as　a　charring　agent　for　chitin　reacted　with　APP　and　MEL　with　the　formation　of　an　intumescent　layer　on　the　surface.