Currently, the Chemical fertilizer industry of agriculture faces backorder and charges from unsuccessful delivery of goods. The researcher studies the problem and presents this research with the objectives. to design the fertilizer packing schedule to suit the customers' unstable behavior of picking up products. The researcher has studied the work process and analyzed the customer's pick-up behavior. It was found that the customer's pickup of goods fluctuated in terms of product type, product quantity, and knowing the date of receiving the product in a time period. In addition, nowadays, customers' behavior of picking up products has changed. Whether from climate change factors or government support programs As a result, the current scheduling concept may not be as appropriate as before and backlogs will occur. From the problems the researcher has studied the theory and relevant research to develop concept of work scheduling combination with product grouping by bringing the ABC classification theory. The result of the research showed that the developed scheduling concept able to reduce the amount of backorder by 0.89%, which can reduce the backlogged fee commission up to 12.07% per month, reduce backlog produce by 6% - 52% per month and increase machine utilization rate by 7.68% per month.