The　hypoxic　microenvironment　and　radioresistance　of　tumor　cells,　as　well　as　the　delay　in　efficacy　evaluation,　significantly　limit　the　effect　of　clinical　radiotherapy.　Therefore,　developing　effective　radiosensitizers　with　monitoring　of　tumor　response　is　of　great　significance　for　precise　radiotherapy.　Herein,　a　novel　radiosensitizer　(term　as:　SCuFs)　is　developed,　consisting　of　traditional　Chinese　medicine　(TCM)　compounds　salidroside,　Cu2+,　and　hydroxyl　radical　(center　dot　OH)　activated　second　near-infrared　window　fluorescence　(NIR-II　FL)　molecules,　which　make　the　radiosensitization　effect　and　boosted　chemodynamic　therapy　(CDT)　efficacy.　The　overexpressed　glutathione　in　the　tumor　induces　the　SCuFs　dissociation,　allowing　deep　penetration　of　the　drug　to　the　whole　tumor　region.　After　X-ray　irradiation,　salidroside　inhibits　the　Nuclear　factor　erythroid　2-like　2　(Nrf2)protein　expression　and　blocks　cells　in　the　G2/M　phase　with　the　highest　radiosensitivity,　which　amplifies　the　reactive　oxygen　species　(ROS)　generation　to　exacerbate　DNA　damage,　thus　achieving　radiosensitization.　Meanwhile,　the　upregulated　ROS　provides　sufficient　chemical　fuel　for　Cu+-mediated　CDT　to　produce　more　center　dot　OH.　NIR-II　FL　imaging　can　monitor　the　center　dot　OH　changes　during　the　therapy　process,　confirming　the　radiosensitization　effect　and　CDT　process　related　to　center　dot　OH.　This　study　not　only　achieves　effective　radiosensitization　and　cascaded　ROS-mediated　CDT　efficacy,　but　also　provides　a　useful　tool　for　monitoring　therapeutic　efficacy,　showing　great　prospects　for　clinical　application.