Abstract: Motion compensation technique is crucially important to image reconstruction of synthetic aperture sonar (SAS).However,phase error caused by motion error varies in the wide slant range,especially for wide-swath synthetic aperture sonar,which makes displace phase center (DPC) algorithm invalid.A motion compensation method based on adaptive time delay estimation is presented.This method utilizes mixed modulated Lagrange explicit time delay estimation (MMLETDE) algorithm to obtain estimation of time delay,then a linear regression model is used to fit motion error.Lastly,raw data can be compensated point by point with the estimated sway and heave.Simulation results show that this method can get better motion error estimation,and actual resolution of images approximates ideal resolution.The method is applied to high frequency and low frequency SAS lake-trial dataset,which shows image qualities of terrain and small targets are both improved evidently.