Nowadays, the global market requires a variety of products and shorter life cycle to fulfill the diverse demands of customers. To survive in the turbulent and competitive markets, automobile assembly companies must design and implement manufacturing systems that respond rapidly to market demands. In this paper, methods for reconfiguring system based on modular concept is proposed using AR(Augmented reality) technologies. First, the relationship matrixes between change drivers and system components are generated to divide existing manufacturing system to each module. And, new change drivers are selected based on required function in new system. Through the modification of relationship matrix, the concept design of new system is proposed and implemented in AR environment. Finally, according to proposed methods and procedure in this paper, the existing cockpit assembly system is reconfigured to spare tire assembly system as a case study. As the use of the modular-based reconfiguration method in AR environment, the time and cost for reconfiguring manufacturing system will be reduced dramatically.