Imbibition，as one of the main methods to improve the degree of crude oil production in tight sandstone reservoirs，has attracted much attention. Measurement errors of produced oil in imbibition tests lead to wrong evaluation of imbibition performance. Taking the Chang 7 Member of the Yanchang Formation of the Luohe Oilfield in the Ordos Basin as the research object，the effects of imbibition time，interfacial tension，wettability，rock physical properties and imbibition pressure on the imbibition efficiency were studied at the microscopic pore scale through experimental methods such as high-pressure mercury injection and nuclear magnetic resonance. The results show that：（1） The pore structure of the Chang 7 Member core is dominated by small pores，and the capillary force is the main driver for imbibition. With 96 hours of imbibition，the imbibition efficiency of cores reaches a plateau，and the imbibition efficiency of small pores controls the imbibition efficiency of the core. （2） Due to the large seepage resistance of small pores，the imbibition efficiency of small pores is affected by both the driving force and resistance of dialysis. With the decrease in core permeability and interfacial tension，the imbibition efficiency shows a fluctuating trend，and with the increase in the wetting angle，it decreases significantly. （3） When the permeability is lower than 1 mD，the imbibition resistance controls the imbibition efficiency. As the permeability increases，the influence of the imbibition driving force is strengthened. The Chang 7 Member core presents the best imbibition efficiency in the case of an interfacial tension of 3.08 mN/m，a wetting angle of 20°，and an imbibition pressure coefficient of 1.45. The findings of this research provide references for improving the interfacial tension，wettability and imbibition pressure of imbibition treatment media.