The main objective of the present investigationto examined the impact of annealing temperaturevarying from 450 °C to 500 °C on bismuth ferrite (BFO)thin films prepared by spray pyrolysis method. The X-ray diffraction (XRD)confirmed that BFO havetypical rhombohedralphase with no intermediate impurity phasespresent in the sample.The average crystallite sizes as calculated using Scherer’s equation found to be in the range of ~15to 20 nm.The crystallite size and microstrain as calculated from Williamson-Hall methods were found to be ~17.67 nm, 22.35 nm 28.54 nm and 0.028, 0.021 respectively.The atomic force microscopy (AFM)revealedthat BFONPs are formed nanorods shape topography,symmetrically distributed throughout on the surface of the films. The surface roughness increases from ~4.56 nm to 7.68 nm with increase the annealing temperature indicates modified the crystal structure of thin films.Thefractal dimension values was observed and found to be 1.64 and 1.96. It to be seen that, increasing values of the fractal dimension with increasing annealing temperature 450 °C to 500 °C respectively. This result indicates that can be employed to describe the variation of theentire grain morphology along direction of the growth. Also, unlikeRMS roughness, the fractal dimension contains spatial information andprofile deviation information.