Nano-sized BiFeO3 were synthesized by sol-gel auto combustion method and report the effect of different annealing temperature (400 °C, 500 °C, 600 °C) on phase formation, morphology, magnetic and dielectric properties of synthesized bismuth ferrite (BiFeO3) nanoparticles. The phase formation of BFO nanoparticles were confirmed by X-ray diffraction pattern. Further, significant increment in particle size with increasing annealing temperature was estimated by field emission electron microscopy (FESEM). Magnetization curve showed the soft ferromagnetic behavior of the samples annealed at 400 OC and 500 OC that was explained on the basis of disturbance of spiral modulated long range antiferromagnetic order of bulk BFO. Dielectric response revealed decrease in dielectric constant with increasing annealing temperature. BFO is a room-temperature multiferroic material so it is potential candidate for various applications viz. Water waste treatment, gas sensors and photovoltaic cells in rural areas.