Survival and development of manufacturing business depends on how the companies make competitive product and put out on the market. In other words, the core competitiveness of manufacturing business is "product" and companies’ competitiveness and sustainable growth could be guaranteed by management from product deveIopment to release onto the market. However, there are few examples about establishing successful system yet. The purpose of this study is to analyze on how PLM affect the performance. In particular, findout how iIlegal copying of PLM system that contains know-how gives company negative effect and emphasize why companies should recognize the importance of iIIegaI copying.