Carbon fiber/epoxy resin composites (CF/EP) have been widely used in aerospace,transportation,wind power and other fields,but due to the long term work in the harsh environment,the surface is easy to be soaked in water,ash,ice and so on.In order to improve the surface hydrophobicity of CF/EP,the mastoid microstructure is fabricated by femtosecond laser processing system,and then the surface morphology of microstructures is measured by white light interferometer and the hydrophobic properties of microstructures are analyzed by contact angle measuring instrument.The effects of laser power and microstructure dimension parameters on the microstructure and hydrophobicity of mastoid are studied.The results show that when the scanning speed and pulse frequency are constant,the contact angle is positively correlated with the input power；when the power is higher than 1.25 W,the contact angle is negatively correlated with the input power；the contact angle of the carbon fiber/epoxy resin surface microstructure decreases with the increase of the radius of the mastoid,and the maximum contact angle reaches 139.7°.Femtosecond laser etching can improve the hydrophobicity of CF/EP surface,and the radius of mastoid is an important factor affecting the hydrophobicity of CF/EP surface.