In this paper, a system architecture of data mining in network based on the technology of Mobile Agent and RDF is presented. This system architecture provides a standard and uniform structured data-platform for the con-crete data-mining application. Mobile Agent implements the concrete data mining application. The relative technolo-gies of this system architecture are introduced first, then two species of logic architecture of the network based appli-cation system are explained. And an accomplished prototyping of network-based data mining system architecture is proposed. The combination of the up-to-date XML/RDF and Mobile Agent technologies provides a new method for data mining in network.