Abstract: The chemical composition of the surface of aramid fiber treated by plasma was characterized by using X-ray photoelectron spectroscopy(XPS).The results showed that carbon content on the fiber surface decreases as plasma treatment time increases,while nitrogen content exhibits little change and the content of oxygen increases in large extent.And increasing plasma treatment time in the scope of this experiment,the total amount of oxygen-containing groups(—C—OH,C()(O,)—COO—,—COOH) has a significant increase.Thus,the chemical action and physical etching of plasma treatment on the surface of aramid fiber will be conducive to the improvement of aramid fiber interface character and favorable for its adhesion to rubber matrix.This research results have provided a theoretical basis for the application of aramid fiber.