The general theory of wavelet transform and the application of wavelet transform in signal de-noising were discussed. Different wavelet de-noising results with different wavelet bases，thresholds and decomposition level were compared . Matlab was used to carry out the simu1ation. Signal to noise ratio (SNR) and root mean square error (RMSE) were used to evaluate the effect of wavelet de-noising. Experimental results show that, the wavelet transform obtain better results in signal de-noising.