he past production method cannot catch up today’s industrial model while production technique and computer technology advance. Computer tools have replaced human planning and provide different solutions under different conditions. Moreover, computer systems have integrated many algorithms and improved production planning. APS system utilizes advance information technology and scheduling technique in order to provide inventory monitoring and production scheduling under limited resource. APS system also provides what-if analysis. Planners are able to combine production conditions and relative information in order to making the best decision to satisfy demand and against competitive market. Therefore, the development of APS system points out restrictions of ERP/MRP. However, APS does not try to replace ERP. APS can improve production planning and scheduling functions from traditional MRP logic of ERP. APS is able to assist planners to make most efficient planning to simultaneous with materials and production. Hence, the relation between APS and ERP becomes important. For enterprises that are installed ERP, how to utilize APS has become the important step before achieving the second step of ERP. In 80s Eligahu M. Goldratt developed TOC to solve management and logical problems. Over ten years TOC has been testify. More and more people are using TOC to improve manage efficiency. This research tries to point out restrictions of ERP/MRP by discussing APS through TOC. By comparing system information, the research inspects the relative planning between each module through TOC.
