Many countries are increasing their focus on the concept of e-government, which is a major resort developing a modern government. E-government is a way for governments to use the new technologies to provide people with more convenient access to government information and services, to improve the quality of the services and to provide greater opportunities to participate in our democratic institutions and processes. E-government presents Macau with some tremendous opportunities to move forward in the 21ˢᵗ century with higher quality, cost-effective, government services and a better relationship between governments and citizens. This thesis models the general typical electronic government services using UML (Unified Modeling Language), which are helpful to develop different e-government systems based on object-oriented software methodology. Meanwhile, several case studies of e-government services (e-task, e-voting, e-payment, e-application, and e-appointment) are analyzed, designed and implemented to illustrate the feasibility of the e-service design by using UML as well as other current widely used techniques (ASP, Java, WAP/WML, and XML). Keywords: electronic government, modeling