Abstract: The mass investigations of the modal acoustic emission(MAE) technology lie in analysis and processing of AE signals were proceeded. Due to every established technology of signals processing, such as FFT, power spectrum, STFT, wavelet, etc, has some shortage, the product of the signals processing is unreliable. So this paper introduced a new technology of signals processing, that is HHT, and discussed the availability and advantage of the technology. Based on the theory of the MAE, the propagation characteristics of the AE signal can be accurately conducted by analyzing the lead-breaking signal in the plate.