Nano MgFe-TiO₂ photocatalyst was prepared by mixing nanoscale spinel compounds such as magnesium ferrite (MgFe) and TiO₂. The cations produced by MgFe are affected by various influencing factors such as calcination temperature, precursor, and mass ratio of Mg and Fe. This study is to evaluate the photocatalytic efficiency of nano MgFe-doped TiO₂ under visible light according to the composition ratio of Mg, Fe and TiO₂. With an increase the percentage of doping (i.e., Mg and Fe) over TiO₂, the band gap between conduction band and valance band decreases, therefore showing better photocatalytic activity in visible light. Also as percentage of doping over TiO₂ increases, surface area of the catalyst also increases subsequently resulting in an increase in the adsorption capacity.