Lead-halide　perovskites　have　received　extensive　attention　in　X-ray　imaging　applications　recently.　However,　their　poor　stability,　lead　toxicity,　and　strong　light　self-absorption　seriously　limit　the　commercial　development.　Here,　we　report　a　vacancy-ordered　Cs2HfCl6　double　perovskite　for　scintillators　applications.　The　Cs2HfCl6　microcrystals　(MCs)　are　characterized　by　broadband　blue　emission　with　a　large　Stokes　shift.　Joined　experimental-theoretical　characterizations　reveal　the　highly　localized　charge　distribution　in　Cs2HfCl6　and　structural　distortion　of　[HfCl6](2-)　octahedron　in　the　excited　state　favor　the　formation　of　self-trapped　excitons　(STEs),　which　contribute　to　the　broadband　emission.　Benefiting　from　the　radioluminescence　of　STEs　with　negligible　self-absorption,　the　light　yield　of　Cs2HfCl6　scintillator　reaches　21700　photons/MeV,　and　the　detection　limit　is　55　nGy(air)　s(-1).　Additionally,　the　Cs2HfCl6　scintillator　exhibits　extremely　low　hygroscopicity　and　good　resistance　to　X-ray　irradiation.　Further,　a　large-area　scintillator　screen　(20x20　cm(2))　is　fabricated　by　combining　scrape-coating　and　soft-pressing　techniques,　showing　a　spatial　resolution　of　11.2　lp　mm(-1).　Given　the　high　spatial　resolution　and　fast　light　decay　of　this　scintillator　screen,　static　X-ray　imaging　of　bulky　objects　is　realized,　and　dynamic　X-ray　imaging　of　a　rotating　chopping　fan　is　demonstrated　without　ghosting　effects.　These　results　demonstrate　the　great　commercial　promise　of　Cs2HfCl6　scintillation　screens　for　indirect　X-ray　detection.