Photocatalytic conversion of CO2 into fuel and value-added chemicals as a promising method has been applied recently to ease energy- or environment-related crises. Herein, we construct an In2S3@NH2-MIL-68(In)@In2S3 (denoted as SMS(In)) sandwich homologous heterojunction via a controllable in situ metal-organic frameworks (MOF) sulfuration process. The improved photoreduction activity mainly lies in the effective charge transfer and separation through a homogeneous interface, enhanced CO2 adsorption and mass transfer, and plentiful reactive sites. Benefiting from this unique hollow homologous heterojunction, SMS(In)-7 obtains a CO generation rate as high as 11.23 mu mol g(-1) h(-1) with visible-light irradiation, nearly 3 times enhancement over that of pure MOF-derived In2S3. This work provides a novel insight into the utilization of MOF-based platform for an efficient atomically heterojunction design.