Nano crystalline Tin oxide thin film of multiple layers was successfully prepared by the sol-gel method with, spin coater has been used to deposit the films. The starting material is SnCl2. The SnO2 material was characterized by X-ray Diffraction (XRD), Scanning Electron Microscope (SEM). The optical properties (A, T, R) of the SnO2 thin film of various annealing temperatures (400,500,600 Co) have been studied. Characterization results indicated that the products are composed of crystalline SnO2 nanoparticles which exhibit the cassiterite-type tetragonal crystal structure. SEM revealed that with increase annealing temperature, the uniformity of the film increased. XRD measurements showed that the grain size increased from 1.06, 1.48, 1.71 nm. The variations of the refractive index (n), extinction coefficient (K) and Optical Conductivity with the wavelength have been studied. Nevertheless, the variation of the optical band gap with film thicknesses shows a significantly decrease in the values of the band gap with increase the film thicknesses.