In order to improve the milling of carbon fibre reinforced polyether ether ketone （CF/PEEK） composites with defects such as burrs， delamination and surface pits， the processing method of ultrasound-assisted milling with CF/PEEK at four fibre orientation angles of 0°，45°，90° and 135° was carried out and compared with conventional milling.The results show that ultrasonic-assisted milling has lower cutting forces and better machining quality than conventional milling. The most significant reductions in cutting forces， surface roughness and burr height are achieved by ultrasound-assisted milling of specimens along a 90° fibre orientation angle， with reductions of 16.79%，28.9% and 71.9% respectively.Furthermore， ultrasonic-assisted milling is effective in improving surface defects such as surface pits and delamination， compared to conventional milling under the same machining parameters.