Abstract: Aiming at the problem that acoustic emission(AE) signal generated in rock fracturing process contains a lot of noise, an acoustic emission(AE) signal noise reduction algorithm with the variational mode decomposition(VMD) and the improved adaptive wavelet threshold(IAWT) is proposed based on zebra optimization algorithm(ZOA). Using ZOA algorithm,the number of modes(K) and quadratic penalty factors(α) that affect the decomposition effect of VMD are selected. The decomposed IMFs are divided into effective, noisy and excluded components by correlation coefficient. In view of the shortcomings of the wavelet threshold(WT) denoising algorithm, which does not automatically adjust the wavelet basis and the large deviation and discontinuity of the soft and hard threshold functions,this paper proposes an IAWT algorithm to remove the noise component in IMFs and then the denoised AE signal is reconstructed with the effective component. Through the verification of simulated and measured AE signals and the comparison with existing denoising algorithms, the results show that the proposed noise reduction algorithm is suitable for processing AE signals, and the time-frequency characteristics of the signal can be retained. The research can provide a reference for AE signal theory and practical engineering applications.