Owing　to　the　biological　compatibility　and　mechanical　properties　of　polylactic　acid　(PLA),　it　presents　an　extensive　application　area　(such　as　packaging,　film,　and　fiber).　However,　the　molten　dripping　phenomenon　during　combustion　is　still　a　drawback　in　the　application　of　PLA.　In　this　research,　an　intumescent　flame　retardant　(A-A)　was　prepared　based　on　the　ionic　exchange　between　p-aminobenzenesulfonic　acid　and　ammonium　polyphosphate.　After　that,　A-A　was　molten　compounded　with　PLA　to　improve　its　flame　retardancy.　It　was　suggested　that　the　presence　of　15%　A-A　could　increase　the　limiting　oxygen　index　value　from　20.0%　of　neat　PLA　to　30.5%,　enhance　the　UL　results　from　none　to　V-0　and　restrict　the　heat　release　during　cone　calorimeter　test.　Most　importantly,　the　dripping　behavior　of　PLA/15A-A　composites　while　burning　had　been　greatly　minimized.　On　the　basis　of　the　mechanism　analysis,　it　was　suggested　that　A-A　modified　the　initial　degradation　routine　of　PLA　matrix,　resulting　to　the　rapid　construction　of　protective　barrier,　thus　endowing　the　antidripping　property　to　the　PLA/15A-A　composites.