A lot of manpower is used in the process of packing cigarettes into shake-lid shaped cigarette case, which results in low production efficiency and easily leads to secondary pollution problem. Vacuum suction manipulator was proposed to conduct this packing process and optimization design was performed for the structure of vacuum chuck in the end of manipulator. FLUENT was used to analyze the 2D flow fields of chucks with three kinds of different structural parameters, obtaining the relationship among vacuum flow field stability and sucker-port structure， degree of vacuum. Simulation results showed that the relationship strength of the vacuum flow field followed the order of Cone> Round> Square; With the increase of the degree of vacuum, the hole inlet flow rate of sucker port center and the suction both increased. The larger the vacuum degree inside the vacuum flow field, the worse the stability. When the vacuum pressure was 20, 25, 30, 40 kPa, the ideal degree of vacuum chuck cone flow field was 20 kPa. The design of cigarettes into the box process was reasonable, stable and efficient. The simulation results could provide theoretical basis for optimization design of vacuum chuck.