In order to detect the obscure target by using lidar (light detection and ranging), the influence of obscure target on lidar echo waveform is studied, and its simulation data are obtained. Fitting the nonlinear waveforms by using Levenberg-Marguardt algorithm, which break down waveforms into a series of Gaussian components, and obtain the number, position, half-width and amplitude of each Gaussian component. Echo components of sub-target in different channels are obtained via time matching of separate sub-echoes respectively; the ratio of reflectivity and depolarization degree are obtained via amplitude of waveform component, which can achieve the characteristic extraction of various targets.