Environmental pollution has significantly influenced ecology and has thus become a global issue. To satisfy diverse market demands and to upgrade product competitiveness, companies have prioritized the production of green products. In the initial stage of new product production, companies need to evaluate green component suppliers for those that meet environmental requirements in product design changes. By following the WEEE and RoHS directives of the EU, and by eliminating component suppliers with negative green indexes, this study constructed an optimal decision-making model for the selection of green component suppliers. The supplier selection was conducted by considering a quantity discount mechanism under the scenario of seeking minimum total cost. Lastly, this study obtained the solution for the model by applying Particle Swarm Optimization (PSO), and constructed a decision support system upon the decision-making process for the reference of decision makers.