Aimed at the problem that the mechanical seal acoustic emission signal is easily interfered by environmental noise and it is difficult to effectively separate from the background noise,the adaptive denoising method of acoustic emission signal combining the complete ensemble empirical mode decomposition (CEEMD) and the improved wavelet threshold denoising method was proposed.According to the characteristic that the energy density of the intrinsic mode function component and its average period are constant after the empirical mode decomposition (EMD) of white noise,the boundary point of the CEEMD signaltonoise component is adaptively determined.In order to effectively avoid the defects of the wavelet original threshold function,the improved wavelet threshold function is used to denoise the highfrequency IMF component,and then the signal is reconstructed with the rest of IMF component to complete the noise reduction process.The noise reduction results of the simulated signals and the mechanical seal acoustic emission signals collected by experiment show the effectiveness and feasibility of the noise reduction method