Synthetic aperture radar to achieve high resolution is based on the premise that the platform is an ideal uniform linear motion. Relative to the traditional microwave SAR, because of the short wavelength of terahertz wave, SAR platform of high frequency micro vibration impact on conventional microwave band SAR is almost negligible but terahertz synthetic aperture radar (THzSAR) must be fine processing.It is necessary to study the imaging compensation algorithm suitable for THzSAR. In this paper, the echo model of THzSAR is established, and the effect of motion error on the echo is analyzed from the time domain and frequency domain respectively. A motion compensation algorithm for THzSAR imaging based on echo data is proposed, the SAR system with center frequency 0.3 THz is used to carry out the experiment, and the 2D image of the corner reflectors is obtained. The experimental results verify the feasibility of the system and the effectiveness of the algorithm, which lays the foundation for the field vehicle or airborne THzSAR imaging.