The main objective of this study was to determine the phytochemical composition from the dried galls of Quercus infectoria, using methanolic extraction and report the main functional components by using infrared (IR) technique. The phytochemical compound screened by gas chromatography-mass spectrometry (GC-MS) method. Twelve bioactive phytochemical compounds were identified in the methanolic extract of Q. infectoria. The identification of phytochemical compounds is based on the peak area, retention time molecular weight, and molecular formula. GC-MS analysis of Q. infectoria revealed the existence of the Cis-p-mentha -1(7),8-dien-2-ol, 3-Nonynoic acid, Urea, N,N´-bis(2-hydroxyethyl)-, 3-Trifluoroacetoxypentadecane, Pterin -6-carboxylic acid, 2,2-Difluoroheptacosanoic acid, y-Sitosterol, Spirost-8-en-11-one, 3-hydroxy-, (3?,5?,14?,20?,22?,25R)-, Curan,16,17-didehydro-,(20xi.)-, 17.alfa.21?-28,30-Bisnorhopane, Ethyl iso-allocholate, Milbemycin B,6,28-anhydro-15-chloro-25-isopropyl-13-dehydro-5-. The Fourier transform-infrared (FTIR) analysis of Q. infectoria proved the presence of alkenes, aliphatic fluoro compounds, nitro compounds, alkanes, hydrogen bonded alcohols, and phenols.