The photocatalytic degradation of rhodamine B (RhB) over chlorophyll-Cu co-modified ZnO catalysts (Chl-Cu/ZnO) was studied under visible-light irradiation. It was found that chlorophyll as an electron donor and copper in Cu2+ form help inhibit the recombination of electron-hole pairs and improve photoactivity of the catalyst. The synergistic effect between chlorophyll and Cu was found to improve visible-light response of ZnO nanoparticles, resulting in excellent performance in photodegradation of RhB. The appropriate ratio of chlorophyll and Cu loadings over ZnO was 0.5Chl-0.10Cu/ZnO-at this ratio, under visible-light irradiation of 2 h, the degradation efficiency was approximately 99% (60 mg/l of RhB solution), of which 18% of RhB adsorption occurred in dark condition. Moreover, outstanding reusability of Chl-Cu/ZnO, for up to six cycles, was found, with more than 80% degradation efficiency.