As e-Commerce and national public procurement have been enabled, needs of supplier management and evaluation system for national public procurement has been growing. Enterprises have constructed and operated supplier relationship management system, in order to automate and increase their supply chain processes by managing the strategic assessment of relationships with external partners. Recently, PPS(Public Procurement Service) in Korea is introducing the concept of SRM to ensure the fairness of public procurement and to strengthen the competitiveness of the national public procurement and public procurement. For this purpose, it is necessary to establish supplier evaluation management and decision support process to allow a transparent supplier selection. In this paper, we present an evaluation method for transparent and objective public procurement. We also present a method for purchase decision support.