Considering the characteristics of pulse waveform of laser echo signal in high SNR which is different from that in low SNR a wavelet filtering algorithm for low SNR Gauss pulse echo signal was studied. The definition of photoelectric detection SNR is introduced and the different SNR pulseecho waveforms are presented in the paper. Then the echo signal accumulation in time domain and smooth filtering algorithm under high SNR conditions are studied. The simulation and analysis of the performance of the algorithm are given. Subsequently for the multiGaussian pulse in the low SNR of the target pulse waveform the lowfrequency wavelet coefficient reconstruction filter is adopted and an appropriate wavelet function and decomposition level are selected by simulation experiments.