In order to clarify the microscopic occurrence state and type of shale oil, and to avoid the influence of water drilling sampling on the distribution of crude oil during the experiment, the typical oil-bearing core of Jimsar shale was selected. The whole process of liquid nitrogen drilling, cutting and grinding was adopted to obtain the microscopic reservoir mineral type and structure, reservoir space type, morphology, and the distribution of C, O, Si, Al, Ca, K, Na, Mg and other elements at the micro- and nano-scale by the combination of full energy spectrum scanning electron microscope, secondary electron imaging and backscattering technology. The enrichment degree of crude oil at the micro- and nano-scale was determined according to the distribution of C element content after removing mineral factors. Combining the mineral rock fabric and reservoir space morphology, the micro- and nano-scale crude oil occurrence states in shale oil was quantitatively characterized. According to the configuration relationship between crude oil and pore-throat, the microscopic pore-throat structure of the reservoir and the occurrence state of crude oil were characterized, and the type of occurrence of crude oil was divided and clarified. Four types of microscopic crude oil occurrence types in the study area were summarized: movable oil in micron-scale macro-pores dissolved by dolomite, movable oil in micro-nano-scale pores between sand particles, semi-bound oil film adsorbed by pore throat walls between sand particles, and authigenic clay minerals bound oil within the intercrystalline pores.