Holospectrum is the spectrum analysis technique which synthesizes the information of the phase, amplitude and frequency. Firstly, the features of the 2-demensional holospectrum were analyzed through the simulating calculation. Secondly, the application of two spectrum correction methods, the phase difference and interpolation method, in the 2-demensional holospectrum technique was discussed respectively. And the result indicates that the former method has better effect for improving the precision of the sine coefficient, the cosine coefficient and the eccentricity. At the end of the paper the 2-demensional holospectrum technique combined with the phase difference method was used to detect three kinds of faults in a multi-functional rotor test rig and the good experimental result was gained.