The packaging carton papers of products need to be checked by quality control machine after printing. Thus,a stack of carton papers shall be taken out one by one and placed onto conveyor belt. A paper picking mechanism composed of two cams and five links（including vacuum suction cups） is designed. By alternate use of inversion-graphic method and fitting of analytical formula,the profile of two cams is obtained.With a higher revolution speed,the proposed paper-picking mechanism can steadily pick 1200 carton papers every minute. Driven by the cam-linkage mechanism,its paper-picking suction cup can move in complex trajectories. Instead of interfering with paper bin,the suction cup is completely fitted to paper bin during paper picking and pauses at the right time to provide negative pressure in harmony with gas path. In this way,a smooth and reliable paper picking process is guaranteed.