The in situ growth of Ag/AgBr on NH2-MIL-125(Ti) was realized via a new strategy. 2-Aminoterephthalic acid and 2,5-Dibromoterephthalic acid were used as the organic ligands to form bromine-amino-bifunctionalized Ti-based MOFs (Br2-NH2-MIL-125(Ti)). Br2-NH2-MIL-125(Ti) was applied as Br source and as the template to support the in situ growth of Ag/AgBr. And the as-prepared samples were characterized by XRD, SEM, TEM, PL, DRS, FTIR, ICP and XPS. Due to the uniform distribution of Br elements in MOFs, Ag/AgBr nanoparticles displayed small and uniform size (about 4 nm). The Ag/AgBr/NH2-MIL-125(Ti) composites exhibited enhanced photocatalytic activity for degradation of methyl orange under visible light irradiation, attributing to the surface plasmon resonance effect of Ag nanoparticles and the formation of heterojunctions between Ag/AgBr nanoparticles and Ti-based MOF. This work may provide a new thinking to construct Ag/AgX/MOF(X = Cl, Br) photocatalysts towards environmental purification and energy exploitation.