X-rays’　high-energy　nature　poses　risks　to　human　health.　Traditional　X-ray　shielding　materials　often　contain　toxic　lead　and　have　drawbacks　like　bulkiness　and　rigidity.　Consequently,　there　is　an　increasing　need　to　develop　lightweight,　non-toxic,　flexible,　and　efficient　shielding　materials.　In　this　study,　we　modified　barite　with　waterborne　polyurethane　(WPU)　and　systematically　investigated　the　effects　of　WPU　on　barite’s　properties.　The　modification　with　WPU　not　only　reduced　the　tendency　of　barite　(B)　to　agglomerate　but　also　enhanced　its　compatibility　with　polymers,　thereby　significantly　improving　the　mechanical　properties　of　LDPE/WPU-B　composites.　Compared　to　unmodified　barite　in　LDPE/B　composites,　the　tensile　and　flexural　modulus　of　the　LDPE/WPU-B　composites　increased　by　22.31%　and　29.64%,　respectively.　With　20%　WPU-modified　barite,　the　radiation　shielding　efficiency　increased　by　5%.　When　the　WPU-B　content　reached　40%,　the　shielding　efficiency　of　the　LDPE/WPU-B　composite　exceeded　90%　for　tube　voltages　ranging　from　60　kV　to　120　kV,　achieving　a　lead　equivalent　of　0.38　mmPb　at　100　kV.　This　novel　LDPE/WPU-B　composite　has　great　potential　for　low-dose　radiation　shielding　applications.　©　2025　by　the　authors.