it is found that the plastic beads product type linear low density polyethylene has a high load and the broken sealing of the bag is the big problem in packaging process, the rate of the defect is at 84.5% comparing with all defects in packing process. The solutions are : defining firstly the problem, analyzing then the principal cause by using the diagram of the cause and the result as an analysis tool, discussing finally with professional area in detail. The outcome shows that there are two main factors of this problem, the first is the length of the bag and the second is temperature at pressing bar. The 3K factorial design was used as the design of experiment. The result shows that the suitable length of the bag is at 760mm and the suitable temperature of pressing bar is at 155C. It was found that, The rate of broken sealing of the bag decreases from 5% to 1.76%, it means that 23,870 baht are saved per month.