In Qianjiang depression, it is difficult to develop the intersalt shale oil reservoir and percolate the crude oil in the matrix. To enhance the efficiency of reservoir development, the reservoir space and the microscopic pore structure of the shale oil reservoir shall be analyzed in depth. Aiming at the intersalt shale oil reservoir in Qianjiang depression, this study carries out quantitative analysis and determines the full-scale pore structure through the high pressure Hg injection, cryogenic nitrogen adsorption and scanning electron microscopy. Result indicates that the pore structures of the shale oil reservoir in Qianjiang depression mainly consists of the nanometer pores in general, with a small number of micron-corrosion pores and microfractures. The pore-throat type of the intersalt shale oil reservoir is single with concentrated distribution. Few number of micro-pore structures is found in the intersalt shale oil, while there is high percentage of mesoporous and macropore. The range of the maximum aperture peak is 40~60 nm, and the range of the main pore is 10~200 nm. Quantitative characterization of microscopic pore structures of intersalt shale oil reservoirs in Qianjiang depression plays an important role in studying the flow mechanism of the shale oil reservoir.