Abstract: This article expounds a novel time-frequency analysis method,i.e.,the Hilbert time-frequency analysis based on Hilbert-Huang transform,and its application to yarn signals.Taking the wool top signal as an example,the article makes a comparison between the short time Fourier transform,wavelet analysis and Hilbert spectrum analysis.The results show that Hilbert spectrum analysis presents a more precise description of yarn signal than the short time Fourier transform and wavelet analysis,so that it can reveal more precisely the variation of energy of yarn signal with frequency and time fields.By analyzing the time-frequency of yarn signal,instantaneous frequency variation can be obtained and then online spectrum analysis of yarn signal can be carried out to perform real-time supervision of the conditions of process and equipment and detection of the abnormality during processing.