To filter the noise in the lidar echo signal and improve its signal-to-noise ratio,a de-noising method of echo signal based on variational mode decomposition (VMD) is proposed.This method uses detrended fluctuation analysis to decompose the signal through VMD,and the relevant and irrelevant modes are distinguished by Bhattacharyya distance.Then,the moving average is used to extract useful signals from the irrelevant modes,and the effective removal of the noise is realized by reconstructing it with the relevant modes.The experimental results show that the output signal-to-noise ratio is increased to 22.58 dB,and the root mean square error is reduced to 0.78×10-11 by this method,which could effectively filter the noise of lidar echo signal and guarantee the integrity of the signal.Compared with wavelet transform,empirical mode decomposition with direct thresholding and variational mode decomposition partial reconstruction,this method has obvious advantages.