Green design and manufacturing is a proactive approach to minimize wastes during a product’s design stage, thus preventing future environmental impacts. Current modular design method mainly focuses on product functional and manufacturing issues. In this paper, a theoretical scheme of multi-objective modularity analysis for discrete electromechanical product design was proposed. Product physical architecture was represented by a fuzzy graph, where fuzzy relationships contain environmental objectives and influence module formulation. Finally the optimal product modules combining all objectives can be searched by clustering algorithm.