In this work, the authors investigate the deposition temperature that governs alteration of the nanoparticle shape in PbSe nanostructure thin films. The experimental data showed that the deposition temperature can alter the shape and optical band gap. The nanoparticle arrays were grown on glass substrate using a facile chemical bath deposition method. The films were characterized by X-ray diffraction, UV-Visible spectroscopy for band gap estimation, and scanning electron microscopy to investigate the particle size and morphology of the thin films. The optical band gap decreases from 2.3 to 1.2 eV with an increase in the deposition temperature.