In order to improve the adaptability of the automatic cartoning machine to different sizes of cartons, the effects of carton height change on the position of the carton blank in the carton magazine and the trajectory of the suction cup in the box picking mechanism were analyzed, and the position adjustment principle of the carton blank magazine was derived under the premise that the reference position of the carton sucked by the suction cup remained unchanged. Taking the position adjustment method of combining the commonly used thread transmission and position indicator as an example, the selection method of tooth joint and lead was given, and the elimination method of adjustment deviation that might exist in the actual design was given. Theoretical analysis and practical tests showed that small adjustment deviations did not significantly affect the normal operation of the boxing unit, and it was not necessary to take measures to completely eliminate it.