A series of novel flowerlike p-BiOI/n-ZnFe2O4 heterostructures has been synthesized via a facile solvothermal method. The phase structures, morphologies and optical properties of prepared nanophotocatalyst were characterized by XRD, FESEM, EDX, BET, FTIR and DRS analysis. The results showed that BiOI/ZnFe2O4 possess much higher visible light activity than pure BiOI and ZnFe2O4 for acid orange 7 degradation. The best photocatalytic activity was 96% according to degradation of acid orange 7 at BiOI/ZnFe2O4(80/20) during 3 h. The improved photocatalytic performance is attributed to p-n structure of composite which facilitates the separation of photo-induced electron-hole pairs. FESEM images showed a flowerlike morphology of BiOI and BiOI/ZnFe2O4 until 20 wt.% loading of ZnFe2O4. According to EDX analysis, BiOl/ZnFe2O4(80/20) sample shows better dispersion of different constituent in comparison to other samples, that provides better interaction between two semiconductors, leads to the great improvement in photoactivity. In addition, the effects of pH, catalyst loading and dye concentration were studied. The results showed that BiOl/ZnFe2O4(80/20) is highly active in acidic media. (C) 2017 Elsevier B.V. All rights reserved.