Abstract: Detailed components on conductor surface such as micro-structure and roughness will affect the electromagnetic scattering behavior of target in terahertz regime. For weighting this impact, the effect of different surface micro-structure on the electromagnetic scattering of terahertz waves from cylindrical objects is studied, as well as its exhibited law in image domain. First of all, multi-angle and multi-frequency scattered fields are derived for polished, surface-defect, and periodic rough cylinders through the use of the high frequency methods in computational electromagnetics. Then, target images are reconstructed using the rotating target imaging algorithm. The corresponding reconstruction images show that surface structures of micron scale still exhibit notable impact on terahertz radar image results. It implies that terahertz radar can attain more fine information about targets, which will supply new characteristics and technical support for target detection and recognition.