Abstract: System architecture and design features of a web browser based multimodal prototype system——NetShop is introduced. It is designed for netshopping applications. We use the context-based interactive query, principal modality driven multimodal integration policy, remedy input and multimodal output to provide a natural interactive environment for this kind of applications. Furthermore, we develop an open speech programming interface using the plugin and liveconnect technology. It not only helps to enhance the flexibility of the whole system, but also provides an easy way for the third party to develop speech enabled web based applications.