Abstract: Filter processing is beneficial to improve the quality of received signal and the measuring accuracy of Very Long Baseline Interferometry(VLBI) system. Spread spectrum signal as wideband signal model, dB1 wavelet function is chosen to wavelet transform for filtering. First, propagation rule of detail coefficients’ maximums and some inferences are proposed and deduced. Then, a novel filter algorithm is proposed, which contains four steps: construction of the highest level detail coefficients, construction of the other level detail coefficients, procession of the highest scale coefficients and shaping of filtering output. Finally, the proposed algorithm is applied to delay estimation in VLBI. Simulation results prove the validity of maximum propagation rule and show a quality improvement of TT&C signal as well as a better performance of delay estimation.