Due to the complex flow mechanism, the characteristics of shale oil elastic development in different areas are quite different. Research has shown that imbibition is one of the important mechanisms, but the imbibition mechanism under reservoir conditions with high-temperature and high-pressure are not clear, and the influence of wettability, pore structure and other factors need to be further researched. Therefore, taking the shale oil reservoir in the Jiyang Depression of the continental fault basin in eastern China as the target, an innovative two-dimensional nuclear magnetic assisted core experiment method was developed to systematically research the elastic development mechanism and high-pressure imbibition mechanism, and to compare and analyze the influence of factors such as wettability, pore structure, and imbibition pressure difference. Experiments shown that the shale oil reservoir in Jiyang Depression had a distinct laminated structure, mainly characterized by water-wet, with non-uniform wetting properties: small pores were strongly water-wet, while large pores were weakly water-wet. In the elastic development, the shale oil in large pores was highly produced. In water-wet pores, the imbibition promoted the fracturing fluid in large pores to enter small pores, thereby improving the recovery of small pores. Moreover, adding surfactants to the fracturing fluid could enhance water-wet, and increased imbibition efficiency by 5%. And increasing the complexity of the fracture networks and the contact area between oil and water can expanded the imbibition paths. If the contact area increases by four times, the oil recovery can be improved by 20%. In addition, increasing the displacement pressure difference appropriately can synergistically couple capillary forces to accelerate the imbibition rate, and the optimal imbibition pressure difference was above 5 MPa. Therefore, water-wet and laminated structure were conducive to imbibition, and appropriately increasing the imbibition pressure difference and constructing complex hydraulic fracturing networks can improve imbibition efficiency and recovery. The research results provided reference for the sweet spots selection, production characteristics analysis, and development strategies optimization in shale oil development.