Abstarct: The rapid development of knowledge and technology has led human beings to use more reliable, faster and more accurate tools in order to meet their needs. The wide range of equipment used in industry and research and daily life depends on the performance of the sensors that includes temperature, humidity, gas, pressure, light and so on are widly being used. But due to the need to modify their performance, extensive research is being done on the sensors. This project seeks to investigate the importance of geometric shape of electrodes in nanostructure gas sensors. Accordingly, in this project first the introduction of nanostructure gas sensor, the importance of these sensors and their application will be discussed and then important parameters in these sensors will be investigated. Following is a review of a research work to modify the structure and performance of nanostructure gas sensors and focus on the role of electrodes in the sensor process. Afterwards the fabrication of the sensor components will be described and the results obtained from this project will be discussed. The results of this study show that the ZnO synthesized by physical vapor deposition (PVD) has a diffraction pattern of the wurtzite structure, which is confirmed by X-ray diffraction of this structure. The FESEM images revealed the nano wires formation with diameter about 35 nanometer.Three samples of sensing components with different geometrical shapes were designed and fabricated for the electrodes and ethanol sensing was performed under different conditions. Experimental results show that the sensor with a squre- spiral electrode has a sensivity of 43% for 2000 ppm ethanol vapor at 200°C while the sensor with an interdigitated electrode has a sensivity of 32% under similar condition. The response time for an interdigitated electrode is shorter than the squre- spiral type and recovery time is almost independent of the electrode geometry. Therefor, the optimum mode should be selected according to the application.