Due　to　their　good　chemical　and　thermal　stability,　high　heat　of　melting,　and　suitability　within　the　desired　temperature　range,　organic　phase　change　materials　(PCMs)　are　widely　used　for　cooling　electronic　devices,　new　energy　utilization,　solar　thermal　power　generation,　industrial　waste　heat　recovery　processes,　and　greenhouse　construction.　However,　the　flammability　of　organic　PCMs　has　limited　their　commercial　viability.　In　recent　years,　researchers　have　been　striving　to　improve　the　flame　retardancy　of　organic　PCMs　through　various　strategies,　raising　the　question　of　which　modification　strategy　best　enhances　the　flame　retardancy　for　different　types　of　composite　PCMs.　Therefore,　a　comprehensive　and　timely　review　is　needed　to　gain　insight　into　the　mechanism　of　action　for　flame　retardant　properties　enhancement.　This　article　firstly　introduces　the　types　of　flame　retardants　and　flame　retardant　mechanism,　and　briefly　introduces　the　test　methods　commonly　used　in　the　laboratory　for　the　analysis　of　flame　retardant　mechanism.　Secondly,　the　strategies　for　improving　the　flame　retardancy　of　organic　PCMs　are　systematically　summarized,　and　some　scenarios　for　the　application　of　organic　flame-retardant　PCMs　are　introduced.　Eventually,　the　challenges　and　future　perspectives　of　the　evolution　of　organic　flame　retardant　PCMs　are　presented.　This　review　is　expected　to　provide　new　insights　for　the　rational　design　of　high　flame-retardant　organic　PCMs.