To utilize the synergistic effect between BiOI and NH2-MIL-125(Ti), a series of BiOI/NH2-MIL-125(Ti) heterostructures with different NH2-MIL-125(Ti) contents were fabricated. The characterization of BiOI/NH2-MIL-125(Ti) was performed by XRD, SEM, TEM, FT-IR, XPS and DRS. The results showed that NH2-MIL-125(Ti) catalysts were highly dispersed on the surface of BiOI nanosheets. Compared to pure BiOI and NH2-MIL-125(Ti) photocatalyst, BiOI/NH2-MIL-125(Ti) composites displayed superior visible light photocatalytic activity. The enhanced photocatalytic performance was ascribed to the formation of heterojunction structure between BiOI nanosheets and NH2-MIL-125(Ti), which significantly suppressed the recombination of photogenerated electron–hole pairs. The optimal content of NH2-MIL-125(Ti) was about 7 wt%, and photocatalytic degradation rate was about 3.8 times and 12.2 times of BiOI and NH2-MIL-125(Ti), respectively. In addition, BiOI/NH2-MIL-125(Ti) composites could keep the photocatalytic activity during the cycle experiment.