Abstract: The self-assembly behavior and optical properties of the hybrid systems involving A(BC)_n multi-block copolymers and nanoparticles were studied by combining dissipative particle dynamics and finite difference time-domain method. The effects of the volume fraction of nanoparticles and the interaction parameters between the different segments on the morphology and optical properties were investigated. Results show that A(BC)_n multi-block copolymer/nanoparticle blends can self-assemble into organic/inorganic hybrid hierarchical nanostructures. The distribution of nanoparticles and the corresponding hierarchical structures have been successfully tuned by varying the volume fraction of nanoparticles and the interaction parameters between the different segments. The effects of different length scales on the reflection of light with different frequencies are significantly different, and the addition of nanoparticles significantly increases the intensity and width of the reflection peaks. The optical forbidden band gaps can be adjusted by controlling the nanoparticle distribution in the hierarchical nanostructures.