A novel capacitive sensor using mesoporous silicon (PSi) layer with a front electrical contact composed of Au-Ti nanostructure for sensitive detection of a group of alcohols in the liquid phase is designed and demonstrated. The PSi layer was firstly synthesized by the photo-electrochemical anodization of single crystalline n-type Si wafer in hydrofluoric acid based etching solution. The electrical contact was smoothly formed onto the front surface (directly exposed to the porous film) using Au-Ti nanocomposite by photolithographic technique and thermal evaporation approach. The as-fabricated PSi-Au-Ti electrical sensor exhibits efficient sensing response with a reversible behavior during the direct exposure and infiltration with liquid methanol and ethanol. However, the response toward propanol and butanol was less efficient and irreversible. The newly-developed electrical sensor was found efficient and promising also for the detection of pure water, which is advantageous for the future sensing ability of aqueous solutions. The observed change in capacitance during the sensing response is related to the generation of a local electrical field at the PSi interface, which led to a shift in the energy level of surface states, generating a modified space-charge region and finally affected the energy distribution and capacitance change.