This work includes the deposition of SnO2 as a thin film on Si (111) by using the pulsed laser deposition method. The influences of oxygen pressure on the structural properties of Tin dioxide films were investigated. The X-ray diffraction results show that the structure of the films change from high polycrystalline to worse polycrystalline at an oxygen pressure of 10mbar. The surface morphology of the deposits materials was also studied by using a scanning electron microscope (SEM) and atomic force microscope (AFM). The results show that, the grain sizes of the nano particles observed at the surface depends on the oxygen pressure. As the pressure of the O2 gas increases the densities of the particles increases too. An oxygen pressure of 5×10-1 mbar was found the best pressure for the growth process. While the RMS roughness was seen to increase with increasing oxygen pressure. It was equal to (11.3 nm) for thin films deposited at (300)ºC.