Radiodynamic　therapy　that　employs　X-rays　to　trigger　localized　reactive　oxygen　species　(ROS)　generation　can　tackle　the　tissue　penetration　issue　of　phototherapy.　Although　calcium　tungstate　(CaWO4)　shows　great　potential　as　a　radiodynamic　agent　benefiting　from　its　strong　X-ray　absorption　and　the　ability　to　generate　electron-hole　(e(-)-h(+))　pairs,　slow　charge　carrier　transfer　and　fast　e(-)-h(+)　recombination　greatly　limit　its　ROS-generating　performance.　Herein,　via　a　one-pot　wet-chemical　method,　oxygen　vacancy-rich　amorphous/crystalline　heterophase　CaWO4　nanoparticles　(Ov-a/c-CaWO4　NPs)　with　enhanced　radiodynamic　effect　are　synthesized　for　radiodynamic-immunotherapy　of　cancer.　The　phase　composition　and　oxygen　vacancy　content　of　CaWO4　can　be　easily　tuned　by　adjusting　the　solvothermal　temperature.　More　intriguingly,　the　amorphous/crystalline　interfaces　and　abundant　oxygen　vacancies　accelerate　charge　carrier　transfer　and　suppress　e(-)-h(+)　recombination,　respectively,　enabling　synergistically　improved　ROS　production　from　X-ray-irradiated　Ov-a/c-CaWO4　NPs.　In　addition　to　directly　inducing　oxidative　damage　of　cancer　cells,　radiodynamic　generation　of　ROS　also　boosts　immunogenic　cell　death　to　provoke　a　systemic　antitumor　immune　response,　thereby　allowing　the　inhibition　of　both　primary　and　distant　tumors　as　well　as　cancer　metastasis.　This　study　establishes　a　synergistic　enhancement　strategy　involving　the　integration　of　phase　and　defect　engineering　to　improve　the　ROS　generation　capacity　of　radiodynamic-immunotherapeutic　anticancer　nanoagents.