UML is a standard language that models an analysis and design process in the development of an application system or components, CORBA, COM+, EJB and others are the techiniques that are realized reuse of components. After it is distinguished between reusable components and new components on the components development process and is developed, the developing cost of components or application system can be reduced and the components of superior in quality can be created. This paper defines the extended UML notation that needed in modeling of the products created from the development process of components. Also, this paper introduces a modeling of components and UML application method that needed in development of an auction system based on Web.