Abstract: The micro-focus X-ray scanning and imaging technology, which has been applied to petrophysical characteristics study on micrometer-nanometer scale, is the most advanced mean for qualitative and quantitative reservoirs description for the time being. Literature research suggests that the technology is currently used to study the rock matrix and the liguid in different kinds of rock pores, and has become a matured qualitative and quantitative technology for oil and gas reservoir description. It can precisely identify the bulk sample, rock matrix and three-dimensional occurrence of pores;rapidly observe and analyze the three-dimensional distribution of rock internal pore space, size and connectivity by perspective imaging of cores. Through the threshold segmentation, we can carry out modeling of three-dimensional pore structure, pore fluid flow network and gas hydrate formation and decomposition for four-dimensional research level. In this paper, the authors analyzed and discussed the principles through application cases of previous studies, and made some suggestions.