The properties of the fiber/matrix interface in CF, GF and FF-reinforced composites play a dominant role in governing the overall performance of the composite materials. Plasma surface modification of the fibers is being studied to promote different effects that can enhance the interfacial adhesion with matrix and/or coupling agents, including (1) the introduction of functional groups on the material surface to promote covalent bonding; (2) the ablation or etching of material, which results in a rougher surface with higher surface are for adhesion; (3) and surface cleaning for enhanced fiber-resin contact. It offers numerous advantages over the conventional chemical wet processes. Plasma surface modification does not require the use of water and chemicals, resulting in a more economical and ecological process.