There are various types of PLM(product liability management) according to corporation management level. It is necessary to develop diagnostic methods and application systems for PLM as well as to establish an efficient PLM system. This paper aims to propose a PLM system which can be applied to product with high-reliability and high-safety, and diagnostic methods for PLM based on AHP, and also show an empirical application of the proposed PL management system for Auto Test Robot System of the Mobile Phone (EVT 4320).