Water pollution by methylene blue dye has become a reason for environmental pollution and has been hostile to the aquatic ecosystem and this wastewater needs treatment. Nano sized, bismuth ferrite (BFO) nanoparticles were prepared via facile sol-gel technique at 450°C, 550°C, and 650°C. The synthesized BFO NPs characterized by scanning electron microscopy, X ray diffraction, and Fourier-transform infrared spectroscopy techniques. The BFO NPs synthesized at 650°C having the smallest crystal size (8.95nm) explored for the catalytic degradation of methylene blue dye in aqueous solution. The effect of different investigational parameters such as amount of BFO catalyst, initial MB dye concentration and degradation contact time on the catalytic degradation of MB studied. The degradation reaction followed pseudo- first-order kinetics with respect to catalyst dosage. In 20-ppm methylene blue, aqueous solution high removal efficiency (97.02%) was achieved by using 10mg BFO at a contact time of 5-min.