Delamination and fuzzing defects during drilling of KFRP composites are too severe to meet the requirements in assembling process. Therefore, orbital drilling is proposed to drill KFRP composites in this study. Single factor experiments are conducted to investigate the hole quality and inhabitation mechanisms in different working conditions. Delamination factor, fuzzing area and diameter deviation are presented to characterize the hole quality. The experimental results indicate that there are close influences of eccentricity, spindle speed and cutter geometry on hole quality. When four-flute end mill with waved edges is used, hole quality is the best in working condition of e=0.5 mm and N=4 000 r/min. The delamination factor and diameter deviation are 1.27 and 1.2% respectively, and reduction of fuzzing area from drilling with two-flute end mill is 13.7%.