Abstarct: Nowadays nanostructured semiconductors are of considerable interests in academic research due to the specific properties they show from themselves. Among these, Zinc Oxide (ZnO) and Tin Oxide (SnO2) nanostructures have numerous applications in many filed such as optoelectronic devices because of their highly functional potential and particular properties. In this thesis synthesis of ZnO and SnO2 nanostructures through Chemical Vapor Deposition (CVD) method have been done successfully by using of a horizontal tube furnace. By varying the effective parameters in synthesis such as source temperature, substrate temperature, synthesis mechanism and Oxygen flow rate, different structures with various morphologies and properties have been synthesized and the effect of these parameters on the synthesis process have been studied. Synthesized samples have been studied structurally and morphologically by using Scanning Electron Microscopy (SEM) and X-Ray diffraction (XRD). These analyzes proved that by varying in synthesis condition different nanostructures are synthesized. The effect of synthesis condition on photo-emission properties of samples have been studied by using Photoluminescence Spectroscopy (PL) in RT and excitation wavelengths of 325 nm and 270 nm for ZnO and SnO2 respectively. Results showed a UV emission along with a broad one in visible region and in different wavelengths for both ZnO and SnO2 samples. The UV and the visible emissions have been related to band to band transition and lattice crystal defects of structures like O2 vacancies, Zn vacancies, SnO2 vacancies and … respectively. It is observed that by reducing the diameter in nanostructures and thus increasing in surface to volume ratio and as a consequence in lattice defects the intensity of visible emission has been increased. For further investigations on photo-emission properties of the samples they have been annealed in different atmospheres. Vanishing the visible emission in PL spectra of a ZnO sample with vacancy of Zn in its lattice crystal have been observed after annealing the sample in Zn vapor.