Organic matter in shale oil reservoir has always been the focus of shale oil research. The organic matter and its micropores in Gulong shale oil reservoir are studied in detail by electron backscattering (HDBSD). It is found that the micropores in the organic matter of Gulong shale oil reservoir are very well developed, which can be divided into four types: ①structural vitroplastid micropores; ②Homogeneous vitrinite micropores; ③Bituminous body micropores; ④Organic clay micropores. The diameter of micron pores in organic matter is from 1 micron to several microns, and the shape is round, nearly round or irregular. Its genesis is related to the residuals of plant bacteria and algae, the volume shrinkage caused by hydrocarbon generation of organic matter and the charging expansion of light oil and natural gas. The preliminary quantitative analysis of micropores in bituminous bodies showed that the micropores accounted for 5. 40%~30. 66% of the surface area, with an average of 19. 53%. It is also found that there is a positive correlation between porosity and organic carbon in Gulong shale oil reservoir. During hydrocarbon generation and expulsion, magmatic hydrothermal interaction is superposed to form a mineral-rich organic multiphase fluid, which plays an important role in the pore-forming reservoir of asphalt bodies and organoclays, forming a kind of spongy organic hydrothermal organoclays rich in organic matter and pores. Preliminary calculation shows that the contribution of organic micropores to reservoir porosity is about 0. 54% (2. 69% for organic carbon). It is reasonable to assume that the (light) oil in organic micropores is a generalized in-situ reservoir. Micron pores in organic matter (including other micron pores) can be connected with higher micro fractures and shale fractures, forming a good spatial connectivity network system, which lays a material foundation for the effective and efficient development of Gulong shale oil.