Abstract: Study of pore-structure characteristics and numerical simulation of microscopic seepage play fundamental and critical roles in gas hydrate research, which are of great significance for understanding the mechanisms of hydrate dissociation, seepage in sediments, and performance in reservoir exploitation. In this paper, several kinds of microscopic detecting technology are used for identification of hydrate-bearing sediments and their technical characteristics. Three widely-used morphological observation methods, including X-ray Computed Tomography (CT), Scanning Electron Microscope (SEM), and Nuclear Magnetic Resonance Imaging (MRI) are introduced with respect to their functions in the study of the pore structure and characteristics of the gas hydrate-bearing sediments. In addition to it, the advances in numerical simulation for the microscopic seepage in the hydrate-bearing sediments by the PNM and LBM methods are discussed and summarized. Based on the above research, we proposed the future directions and challenges for pore-structure research and microscopic seepage numerical simulation for hydrate-bearing sediments.