Novel ZnFe2O4/BiOI nanocomposites were successfully fabricated via simple method. The photocatalytic performance of ZnFe2O4/BiOI nanocomposites was investigated. ZnFe2O4/BiOI nanocomposites exhibited efficient visible-light photocatalytic activity. Visible-light photocatalytic mechanism of ZnFe2O4/BiOI nanocomposites was discussed. Enhanced activity was attributed to efficient separation of photogenerated e− and h+.