In this work both of desizing and etching (thermally and chemically) for carbon fiber surface was performed. To investigate their effect on the mechanical properties on the fiber and it s composite. Acetone and ethanol are used for desizing, as well as heating up to 380? . Etching of fibers is one of the suggested methods to improve adhesion between carbon fiber and matrix. Etching of carbon fiber under atmosphere as a function of temperatures for (380,400,420,500,520) ? and nitrogen gas as a function of temperatures for (500,520,540,560,580,600) ?. The result shows that nitrogen gas give the best etching comparing with atmospheres and this reflects on the mechanical properties of the composite material. Nitric acid, sulphuric acid and hydrogen peroxide are used for chemical etching. Scanning electron microscope (SEM) and contact angle tests on desized and etched carbon fiber show better mechanism for adhesion. The mechanical properties of the treated composites was higher values than those of untreated composites.