Lead sulphide (PbS) thin films with three different molarities were prepared by chemical bath deposition method on glass substrate using lead acetate as Pb2+ion source and thiourea as S2− source. Ammonia solutions were used as complexing agent and to raise the pH value. The as-prepared films were characterized by using X-ray diffraction (XRD). EDX. X-ray fluorescence (XRF), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) for the structural, elemental and surface analysis respectively. Optical absorption was studied by UV-VIS spectrophotometer. The average crystallite size obtained from XRD spectra varies from 17.2 nm to 21.9 nm with increase of molarity. Surface studies reveal rough and uniformly distributed PbS thin film. Optical studies show the decrease of band gap from 1.55 eV to 1.45 eV with higher molarity.