Metal–organic frameworks (MOFs) are extremely promising candidates for application in diverse fields. However, a limitation to the widespread use of MOFs is the absence of a facile and efficient chemical modification method which can greatly improve their poor processability and stability without altering the inherent outstanding chemical and physical properties. Herein, we report a universal post-synthetic modification strategy by directly forming polymer brushes on MOF surface without any premodification or immobilization of initiators via UV-induced photopolymerization. The method is applicable to a series of representative MOFs, allowing the creation of polymer brushes on the exterior surface of nanoMOFs and MOF membranes. Characterization of the polymer brushes indicates a high grafting density of grafted polymer chains, thus endowing MOFs with improved thermal/chemical stabilities with the inner chemical structure and porosity intact. Moreover, the polymer modification facilitates an efficient removal of organic dyes from water solutions.