In the previous work, through discrete cosine transform and digital refocusing, the terahertz optical field image preliminarily realized image denoising，as well as foreground and background segmentation. In order to further obtain higher quality terahertz optical field original data and achieve more accurate depth segmentation, the experimental scheme and processing method are improved, and a terahertz optical field depth estimation method based on epipolar plane image is proposed in this paper. On the basis of terahertz image characteristics, the relationship between depth and disparity is given, and the global depth map is constructed by using local parallax and confidence, so as to achieve depth estimation. Finally, experiments are performed by collecting terahertz light field data from camera array. Results of accurate refocusing on different planes and a high-resolution depth estimation map are obtained, and the depth estimation of terahertz optical field imaging is realized.