An improved denoising algorithm is presented based on the filtering algorithm of correlation of wavelet coefficients. The denoised wavelet coefficients are smoothed by median filtering，and then the denoised signals are reconstructed by the new wavelet coefficients. Simulation results show that the improved algorithm effectively reduce the glitch and the noise. At the noise ratio of 5 dB?15 dB, the indexes of Root Mean Square Error(RMSE) and smoothness of the improved algorithm are better than that of the original algorithm.