Terahertz scattering characteristic acquisition of targets by radar imaging is an important way of scattering measurement, and its premise is to obtain the high resolution and fine imaging results.Aimed at the problems that measurement of imaging in terahertz radar system is difficult to guarantee a complete consistency between the target center and the turntable center during measurement,and the results of imaging are sensitive to position error of targets for the near field terahertz radar system, in this paper, a corresponding accurate imaging model is deduced and established, a method of distance error compensation based on prior information is presented, and a realization of imaging algorithm is proposed, achieving the target’s high resolution fine image acquisition under condition of near field and large rotation angle. The experimental results show that the proposed imaging method can accurately correct the image distortion and defocus caused by the positioning error and near-field factors of the target, and is not subject to the coincidence of the center of the target coordinate system and the radar coordinate system. The study could pave the way for image-based target scattering feature extraction and scattering center diagnosis in terahertz band.