This　paper　proposes　a　high-efficiency　internal　curing　method　for　ultra-high　performance　concrete　(UHPC),　using　perforated　cenospheres　(PCs)　as　water　reservoirs　via　an　equivalent　substitution　to　fly　ash　by　volume.　The　results　demonstrated　that　water-loaded　PCs　effectively　increased　the　internal　relative　humidity　and　significantly　reduced　the　autogenous　shrinkage　of　UHPC.　The　method　of　incorporating　PCs　played　a　crucial　role　in　the　compressive　strength　of　UHPC.　When　PCs　served　as　an　equivalent　substitution　for　fly　ash,　they　helped　sustain　the　compressive　strength　of　the　prepared　UHPC.　However,　when　used　as　the　substitution　for　quartz　sand,　they　led　to　a　significant　reduction　in　compressive　strength.　Moreover,　the　internal　curing　effect　facilitated　by　water-loaded　PCs　led　to　the　formation　of　more　hydration　products,　especially　high-density　and　ultra-high　density　C-S-H　gel,　contributing　to　obviously　refined　pore　structure　of　UHPC　and　a　0.34—4.44　%　increase　in　compressive　strength　at　28d.　The　features　of　fine　sizes,　good　pozzolonicity,　sphere　shapes,　and　high　water-absorption,　combined　with　the　equivalent　substitution　approach,　make　them　superior　to　other　porous　reservoirs.　©　2025　Elsevier　Ltd