In this paper a humidity sensor based on Photoluminescence (PL) response of porous silicon (PS) to specific amounts of organic vapors of ethanol, n-hexane and trichloroethylene in gas phase. PL quenching measurements in a controlled humidity atmosphere mixed Nitrogen gas and water vapor were performed to test the sensor response towards the water vapor. Surface morphologies of the PS samples were characterized by an atomic force microscopy (AFM), structural properties were investigated via X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy, reflectivity for bulk and PS is investigated. The PL for the sample is determined in air and different organic vapor chemical like Ethanol, n-Hexane and Trichloroethylene.