Abstract: ：In order to solve the problem of expensive and single function of the traditional oscilloscope, this article describes the development of dual-channel virtual oscilloscope under the condition of not high sampling frequency based on personal computer’s sound card instead of data acquisition card and LabVIEW software. The main functions of virtual oscilloscope include data acquisition, parameter measurement, waveform display,spectrum analysis, et al．The practice shows that the virtual oscilloscope is not only realize the basic function of traditional oscilloscope, but also a short development cycle, reliable operation and good performance, et al.

Key words: virtual instrument, oscilloscope, sound card, data acquisition, LabVIEW