Abstract: In order to improve the surface wettability of carbon fiber/resin composites, the surfaces of composites were treated by plasma directly. By means of contact angle measurement, tensile test, metallographic microscopic analysis and infrared spectruma nalysis, the best treating technology of carbon fiber/resin composites treated by plasma,mechanical properties and surface functional group changes of carbon fiber/resin composites before and after treatment were investigated. The results indicate that the current, pressure and treating time all have significant influence on the surface wettability of carbon fiber/resin composites, when current is 1.0 A, pressure is 1.0 Pa and treating time is 10 min, the surface wettability is optimal. The tensile strength of carbon fiber/resin composites does not decrease after treatment, while goes up of 8%. Infrared spectrum analysis shows that the ester group chain on treated carbon fiber/resin composite surface breaks and the quantity of eater group decreases. Accordingly, more ketone group, carboxyl group and alcoholic hydroxyl group are formed. The surface polarity is enhanced and wettability is improved significantly.The research solves the problem that the carbon fiber/resin composite surface is unreactiveness, and establishes the foundation for the surface function coating preparation.