The samples of shale oil reservoirs from the Qian34 formation of Qianjiang Sag in Jianghan Basin were collected for a series of experimental studies including core description，thin section analysis，Argon Ionization-Field Emission Scanning Electron Microscopy（AIP-FESEM）analysis，low-temperature nitrogen adsorption，high-pressure mercury injection，etc. to analyze the characteristics of lithologic facies，reservoir storage space types，reservoir physical properties and their influencing factors. The results indicate that the inter-salt shale oil reservoirs in Qian34 are characterized by complex mineral composition. There are six types of lithofacies in the study area，which includes layered dolomite（argillaceous）calcium mangerite lithofacies，laminated argillaceous dolomite lithofacies，laminated dolomite mudstone lithofacies，laminated argillaceous limestone lithofacies，laminated lime mudstone lithofacies and massive dolomite lithofacies. The main reservoir storage space of inter-salt shale oil are interlayer fractures，intercrystalline pores，intercrystalline dissolved pores and clay intracrystalline pores. The average porosity is 11.4%-18.9% and the average permeability is 2.635-4.827 mD. The formation belongs to mid-porosity and extra-low permeable formation. Laminated argillaceous dolomite lithofacies and massive dolomite lithofacies are the most favorable facies types with good physical properties and high oil-bearing characteristics. Compaction and authigenic sulfate minerals filling are the main reasons for the poor physical properties of the reservoir.