This paper introduces a basic concept of network virtual instrument and presents a solving scheme based on the .net framework for web network virtual instrument in which the component technology are used to construct UI component, data-service component, signal-processing component, DB-component, controlling component and data-acquiring component, in accordance to demand these component above can be flexibly put on the right place to realize remote test and control. In the light of the scheme, a set of network oscilloscope based on web is designed to remotely sampling data, and the technology of data base is successfully used to administer the saving and taking of signals in network virtual instrument .