HilbertHuang transform decomposition demonstrates superiority in dealing with nonstationary signals, but for the upwelling weak signal under the background of strong noise in deepsea environment, there will be serious modal confusion when directly extracting the main component of EMD. In order to decrease the noise influence upon the EMD, first wavelet denoising on noisy signal is presented. Then the EMD is decomposed. Through theoretical analysis and computer simulation, it was proved that the method to 〖JP2〗overcome the noisy interference of using EMD directly. The efficiency and accuracy to noisy signal with EMD decomposition are improved.〖JP〗