Phase　Change　Cooling　Clothing　(PCCC)　is　a　promising　wearable　device,　which　can　reduce　thermal　discomfort　and　health　risks　associated　with　high　ambient　temperatures.　However,　most　of　the　existing　PCCC　are　developed　for　special　types　of　work,　with　long　cooling　time　but　heavy　weight,　which　are　not　suitable　for　daily　life　and　work.　Therefore,　this　study　proposes　a　novel　ultra-light　modular　phase-change　cooling　clothing　for　short-term　thermal　discomfort　in　daily　life　and　work.　Firstly,　based　on　heat　balance　theory,　the　heat　transfer　process　of　people　wearing　PCCC　is　modeled,　and　a　calculation　method　for　the　minimum　charge　of　phase　change　material　(PCM)　is　proposed.　The　weight　of　the　PCCC　is　only　1390g　for　keeping　thermal　comfort　over　30　min.　Then,　the　modular　structure　is　proposed　to　make　the　PCM　solidification　more　convenient　and　the　optimal　arrangement　of　the　PCM　modules　is　determined.　Finally,　the　thermal　comfort　before　and　after　wearing　the　PCCC　in　different　scenarios　were　tested.　The　cooling　effects　are　significant　and　the　average　skin　temperature　of　the　subjects　decreases　by　1.35,　1.10　and　1.78　?C　respectively　after　wearing　the　PCCC　under　three　conditions　of　outdoor　walking,　indoor　sitting　and　indoor　walking.　The　proposed　PCCC　has　the　advantages　of　light　weight,　proper　structure　and　good　effect,　which　is　suitable　for　people＇s　daily　life　and　work.