Surface modification of argon-plasma-pretreated poly(tetrafluoroethylene) (PTFE) him via UV-induced graft copolymerization with glycidyl methacrylate (GMA) was carried out first. Reactive adsorption of gamma-aminopropyltriethoxysilane (APS) onto the GMA graft-copolymerized PTFE (GMA-g-PTFE) film surface was performed by the simple immersion of the film in the APS solution. The adsorption process was studied as a function of the APS concentration, the immersion time of the graft-modified PTFE film in the APS solution, and the washing protocol. The chemical composition and morphology of the silane-modified surfaces were characterized by X-ray photoelectron spectroscopy and atomic force microscopy, respectively. The performance of the silane-modified PTFE surface in adhesion promotion was investigated. The T-peel adhesion strength of the evaporated Cu on the PTFE film with the reactively adsorbed organosilane increased significantly to about 12.5 N/cm. This adhesion strength was more than twice that of the assembly involving evaporated Cu on the GMA-g-PTFE film and about 10 times that of the assembly involving evaporated Cu on the Ar-plasma-treated PTFE film.