Abstarct: Due to the increase in hazardous gases in the environment and Human Workplace, study the environment in order Controlling and preventing accidents related to these gases is vital. Gas sensors Semiconductor mextal oxide due to sensitivity and proper response, low cost, simplicity of construction and ... Researchers have been focusing on it for decades, with the advent of nanotechnology in the field of sensors The mentioned sensors have made considerable progress however the mentioned sensors if in order Activation to use heat has limitations that specifically do not use They are used to measure flammable and explosive gases. In order to fix the defects of the sensor under Temperature Other ways such as ultraviolet radiation can be used to activate the sensor. In this project, the applicability of ultraviolet radiation in activating zinc oxide nanostructured sensors has been investigated and ethanol vapor has been used as the target gas. The zinc oxide nanoparticles used were synthesized by hydrothermal method and FESEM, XRD, PL and UV-Visible characterizations were performed on the sample. Zinc oxide nano sheets synthesized under ultraviolet radiation at 360 nm and 390 nm showed a good response to ethanol vapor at a concentration of approximately 500 ppm. Also, by changing the wavelength and intensity of radiation, the effect of these two factors on Zinc oxide sensor was investigated. Then, some other properties of the sensor such as sensitivity and selectivity were investigated under the optimal intensity of wavelength 390 nm and also to evaluate the response of the sensor under temperature and a brief comparison between activation under temperature and radiation, ethanol vapor was measured at different temperatures; The results showed a significant improvement in the performance of the sensor under ultraviolet radiation relative to the heat activation mode, and this promised to gas sensing under room temperature with low risk and low energy consumption. Zinc oxide, Ultraviolet radiation, mextal oxide semiconductor, Gas sensor