目前经典信号处理技术，即时域分析和频域分析，尚不能很好地适应许多科学领域中普遍存在着的非平稳信号的分析，我们把已发展起来的三种时频分析方法：短时傅里叶变换、Ｗｉｇｎｅｒ分布及小波变换，应用到非平稳信号分析中，对这三种方法的原理、性质、优缺点及实际应用逐一进行了论述。 At present, the classical signal processing techniques, that is, the time domain analysis and the frequency domain analysis, are not well adapted to the analysis of nonstationary signals that are common in many fields of science. We have developed three time-frequency analysis methods Fourier transform, Wigner distribution and wavelet transform are applied to non-stationary signal analysis. The principles, properties, advantages, disadvantages and practical applications of these three methods are discussed one by one.