Improving　the　stability　and　charge　transportation　efficiency　of　lead　halide　perovskites　is　the　key　for　their　practical　photocatalytic　applications.　Herein,　we　designed　and　synthesized　a　microporous　boron　imidazolate　framework　(BIF-122-Co)　by　cross-linking　boron　imidazolate　ligands　and　benzene　carboxylate　with　metal　ions,　which　was　further　used　as　a　host　matrix　to　encapsulate　CsPbBr3　perovskite　via　a　sequential　deposition　route　to　obtain　a　composite　material,　CsPbBr3/BIF-122-Co.　Due　to　the　intimate　host-guest　interfacial　contact　in　the　composite　material,　BIF-122-Co　not　only　provided　a　physical　protective　barrier　for　CsPbBr3　but　also　accelerated　the　photoinduced　charge　separation　process　in　the　photocatalytic　CO2　reduction　reaction.　The　work　provided　a　guide　for　exploration　of　excellent　perovskite/metal-organic　framework　(MOF)　composites.　©　2021　American　Chemical　Society.