The virtual oscilloscope based on LabVIEW can realize the dual channel output of waveform，display various basic waveforms and Lissajous figure，observe the influence of frequency，phase and other parameters on waveform，and measure the frequency and phase difference of unknown signals．The waveform and experimental data are saved in the form of picture．This virtual oscilloscope is simple in operation and has various functions．The experiment operation is simplified and visualized and the experiment efficiency can be improved．