The design system can be seen as the environment where design projects (product or system design) take place. The aim of this paper is to optimise the synchronisation and the coordination of the development of several design projects in the design system with limited resources and therefore satisfy the strategic performance objectives of the enterprise. With this intention, this paper deals with the role of the PLM in the system evolution management. In a first time, we analyse the PLM concept and we define the impact of the product along the system lifecycle. Then we identify the relations between the product and system co-evolution and the continual improvement process of an enterprise. We focus on the different natures of the product regarding to the decisional level during the strategic business management. Lastly, we present a prototype of software that integrates the PLM concepts and manages design system evolution.