Service Oriented Architecture (SOA) has become one of the hottest subjects in academic and industrial study for recent years due to the flexibility to integrate heterogeneous information platform and with technology standard for implementation. The development processes of SOA include steps such as service-oriented analysis, design, coding, testing and deployment, but there’s no standard method to implement these steps. UN/CEFACT’s Modeling Methodology (UMM), developed by United Nations Centre for Trade Facilitation and Electronic Business (UN/CEFACT) Working Group, is a methodology to extract the business knowledge and represented using Unified Modeling Language (UML). This study develops a method, based on the Business Domain View (BDV) and Business Requirements View (BRV) models of UMM, for deriving business service candidates in SOA. Additionally, this study adopts the e-plan of Customs Quarantine Control (e-CQC), a project regarding e-Government of Taiwan, as a case study to illustrate the process to derive business services. This method provides a comprehensive way to help enterprises or government to derive business services that can lead to obtain the application services for implementing SOA.