In　this　work,　a　novel　single　molecule　flame　retardant　(DT-S)　was　synthesized　through　the　self-assembly　of　diethyltriamine　penta-(methylphosphonic)　acid　and　sulfanilamide.　Additionally,　the　three-dimensional　sea　urchin-like　layered　double　hydroxide　hollow　dodecahedral　structure　(MOFs-LDH)　was　etched　from　a　MOF　to　increase　specific　surface　area　and　reaction　sites.　The　chemical　structures　of　DT-S　and　MOFs-LDH　were　comprehensively　characterized.　Subsequently,　the　obtained　flame　retardants　were　molten-compounding　into　PLA　matrix.　The　fire　performance　of　PLA　composites　was　evaluated　by　limiting　oxygen　index　(LOI),　vertical　combustion　(UL-94),　and　cone　calorimeter　tests.　Compared　with　neat　PLA　sample,　the　inclusion　of　3　%　DT-S　and　2　%　MOFs-LDH　led　to　an　increase　in　the　LOI　value　from　19.9　to　35.0　%,　an　upgrade　in　the　UL-94　rating　from　none　to　V-0,　and　a　reduction　in　the　peak　heat　release　rate　from　524.4　to　401.2　kW　m(-2).　Analysis　of　the　decomposition　products　of　the　PLA　composites　and　the　observation　of　char　morphology　suggested　that　DT-S　and　MOFs-LDH　took　effects　in　both　condensed　phase　and　gas　phase.　Furthermore,　the　evaluation　of　the　UV　protection　performance　using　a　UV-visible　near-infrared　spectrophotometer　indicated　an　enhancement　in　the　UV　protection　performance　of　PLA,　achieving　an　＂excellent＂　level　in　evaluating　UV　protection　performance　(UPF　50+).