To　improve　the　energy　efficiency　and　photo-thermal　performance　of　a　double-layer　PCM　glazing　window　(DP),　multilayer　PCM　glazing　windows　integrating　DP　(combination　structures)　with　installations　and　low-e　coating　have　been　developed.　However,　the　energy　efficiency　of　a　multilayer　glazing　window　is　not　higher　than　DP　in　all　climate　zones.　The　selection　of　the　appropriate　optimization　strategy　of　DP,　i.e.,　selecting　the　most　energy-saving　multilayer　glazing　window,　should　take　into　account　the　specific　climatic　conditions.　In　this　study,　five　PCM　glazing　windows　(DP　and　four　multilayer　combination　structures)　are　proposed.　Physical　heat　transfer　and　mathematical　models　were　conducted　to　numerically　investigate　the　thermal　and　energy　performance　by　Fluent　in　different　climate　zones　in　China.　Evaluation　indexes　for　different　climate　zones　were　established,　and　the　energy-saving　potential　of　each　PCM　glazing　window　was　compared,　and　the　resulting　combination　structure　with　the　most　energy-saving　potential　in　each　climate　zone　was　regarded　as　the　optimization　strategy　of　DP.　The　results　demonstrated　that　DP　with　the　external　silica　aerogel　has　been　identified　as　the　optimization　strategy　for　severe　cold　zones　with　40.28%　of　energy　saved,　but　it　increases　energy　consumption　in　mild　zones　and　hot　summer　and　warm　winter　zones.　DP　with　an　external　air　layer　and　internal　low-e　coating　is　considered　for　the　optimization　strategies　for　cold　zones,　hot　summer,　and　cold　winter　zones,　and　hot　summer　and　warm　winter　zones,　with　energy-saving　potential　rates　up　to　40.67%,　46.42%,　and　46.99%　respectively.　However,　it　increases　energy　consumption　in　mild　zones　and　cold　zones.　In　addition,　DP　is　proven　to　possess　the　lowest　energy　consumption　in　mild　zones.