As Internet is rapidly emerging as a largescale distributed computing platform, service customization and on-demand computing become an important research issue. Program mining is a novel computingparadigm to achieve this goal through dynamically component discovery and composition from on-line component repositories^1. However, components in different repositories are described and classified in ad hoc ways, laying obstacles for the provision of program mining. In this paper, we present an XML-based component description method, depicting the static properties, interface specification and classification information of software components in a standard way. Based on this description, distributed component directory can be established to provide a wellorganized mining resource for program mining.