Research results: The analytical results show that the regular waveforms in track random irregularities, such as sine wave and triangular wave, could be identified with wavelet method. The high frequency defects on local rail could be checked better with wavelet method. Thought wavelet, the obvious track irregularities (characteristic track irregularities) in every range wavelength could be recognized, which is helpful for making more analysis of these track irregularities. So, analysis of track irregularities from the time-frequency point of view with wavelets is a new technical method for guaranteeing the safe running of railway.