Both the power spectrum analysis and the sound intensity analysis are based upon the Fourier analysis and are widely used for sound analysis. And as wellknown, they can perform poorly in the case of unsteady or tarnsient sound. For such unsteady signals, the time-frequency distribution functions can provide much clearer interpretation. We have been working to apply the Wigner-Ville Distribution (WVD) to the transient sound analysis and the transient sound intensity analysis. In this paper, basic theories and a practical way of calculation are explained. In addition, an analysis example is introduced. The WVD can be used as a powerful tool to analyze rapidly changing signals or to detect abnormal impact noises buried in machinery sounds.