A virtual experiment platform for signal analysis and processing based on LabVIEW is developed. Combined with basic principle and method of signal analysis and processing closely six extensible and workable virtual experiment modules are designed. These modules include signal generator, time domain and frequency domain analysis module, band-pass filter, modem, power-spectrum analysis and boundary checkout of sine signal. A simulation and analysis module of shaft orbit is developed on that basis. In the module some shaft orbit shapes corresponding to typical failures of rotors can be simulated, and the amplitude and frequency spectrum of radial displacement of rotor can be analyzed in real time.