This article studies the CNC machining methods of square window of T300/ AG80 carbon fiber cylindrical composite, with the high speed drilling and grinding CNC machine tools for carbon fiber reinforced plastics.According to structure and characteristics of the material properties, optimized process parameters and CNC programs for processing the square cylindrical module are obtained with spindle speed of 6 000 to 18 000 r/ min and feed rate of 5 to 25 mm/ min, which makes the realization of the automatic processing of the columnar module window of CFRP.