The present study aimed to investigate the effect of calcination temperature on the physical properties and photocatalytic activity potassium ferrate nanostructure as an adsorbent for organic dyes under visible light. The samples were synthesized using thermal treatment method based on the structural formula K2FeO4 at a temperature ranging from 350, 450 and 550 °C, and physical and structural properties of nanostructures were investigated using different characterization techniques. The dye was removed from aqueous solution via potassium ferrate nanostructure oxidation, and the samples were individually exposed to UV radiation. During the mechanism for MB degradation, hydroxyl radicals and photo-hole ( h+) were found to contribute to the MB decay. Based on the results, the presence of H2O2 was not so effective, while H2O2 accelerated the photodegradation. Finally, the results of photocatalytic activity test using a solution of Methylene Blue reveal that the highest photocatalyst efficiency was achieved by potassium ferrate nanostructures in the absence of H2O2, which is calcined at a temperature of 350 °C and after the irradiation for 180 min, with 76.42% in the optimum concentration of 10 mg/l.