An ideal photocatalysts is expected to not only involve nanoscale subunits with high catalytic activity, but also possess a 3D hierarchically porous microstructure to obtain more activated sites as well as easy recovery. Herein, we demonstrated an efficient route to synthesize self-support hierarchically porous TiO2-MnTiO3/HACFs (hollow activated carbon fibers) heterojunction photocatalysts with tunable band gaps by a facile biotemplated method. The heterojunctions with suitable TiO2/MnTiO3 ratios on HACFs supports had fascinating 3D hollow fiber morphology and exhibited exceptionally synergistic adsorption-photocatalytic activities in visible-light degradation of methylene blue (MB). The photocatalytic degradation rate of MB could reach 99.1% in 60 min under visible light irradiation and cycled experiments showed stably photocatalytic activities. The enhanced photocatalytic performance could be attributed to the high efficiency of electron separation, the high specific surface area and strong adsorption ability toward the MB molecule, and the tunable visible light absorption of TiO2-MnTiO3/HACFs.