Nanostructured MgFe2O4 magnetic photocatalysts are facilely synthesized by 60Co γ-ray irradiation assisted polyacrylamide gel route. The influence of different irradiation doses on the morphologies, phase purity, energy bandgap, magnetic properties and photocatalytic activity of the as-prepared MgFe2O4 nanoparticles were studied. The experimental results demonstrate that the phase purity, particle size, morphology, energy bandgap, magnetic properties and photocatalytic activity of MgFe2O4 nanoparticles can be manipulated by the different irradiation doses. In particular, γ-ray irradiation improves the photocatalytic activity of MgFe2O4 nanoparticles significantly. These MgFe2O4 nanoparticles showed high efficiency for the degradation of methylene blue with simulated sunlight irradiation. These results bring up new ideas for the design of nanostructured MgFe2O4 magnetic photocatalysts with tuned magnetic properties and photocatalytic activity through a 60Co γ-ray irradiation assisted polyacrylamide gel route. Schematic representation of the polymerization reaction for MgFe2O4 nanoparticle synthesis, starting from acrylamide and bis-acrylamide (left). Mg-ferrite magnetic photocatalysts were synthesized by γ-ray irradiated assisted polyacrylamide gel route. Optimized utilization of irradiation dose, and sintering temperature allowed the formation of Mg-ferrite nanoparticles with a narrow size distribution. In particular, γ-ray irradiation improves the magnetic properties and photocatalytic activity of MgFe2O4 magnetic photocatalysts significantly. This MgFe2O4 nanoparticles showed high efficiency for the degradation of methylene blue (MB) with simulated sunlight irradiation.