To enhance the interfacial adhesion between the glass fiber and PTFE resin, we have modified glass fiber surface by plasma treatment under trifluoromethane(CHF$_3$) atmosphere. Several parameters, such as plasma power and treatment time in the plasma surface treatment were controlled to obtain the optimum interfacial adhesion. The highest interfacial strength, evaluated by the microdroplet method, was obtained at plasma power of 60W, treatment time of 5 minutes under the flow of CHF$_3$ at 70 sccm. In addition, corrosion resistance of the CHF$_3$ plasma treated glass/PTFE composites was investigated after immersion in the phosphoric acid for 48 hours.