Abstract: In order to find out the key quality indexes of composite cardboard packet blank in production and inspection, the correlation between the indexes and their influences on machine adaptability were investigated. The results showed that:1) The flatness at front end, middle portion and rear end, grammage, thickness, kinetic friction coefficient, stiffness of No.3, 4, 5 fold lines, stiffness in mechanical direction significantly influenced the adaptability of the blank. 2) With the increase of blank thickness, rejection rate decreased and machine efficiency showed an upward trend; however it was on the contrary when the stiffness of No.3, 4, 5 fold lines increased. 3) The optimal indexes combination was the flatness at front end, middle portion and rear end 1.0, -1.1, -1.2 mm, grammage 247.1 g/m², thickness 0.33 mm, kinetic friction coefficient 0.187, stiffness of No.3, 4, 5 fold lines 68.0 g, stiffness in mechanical direction 14.0 g. 4) At the optimized quality indexes, machine shutdown reduced by 17.65 percentage points, machine efficiency raised by 7.65 percentage points, and the rejection rate of cigarette packets decreased by 35 packets per million cigarettes. The optimized packet blank presents better running characteristics.