In recent years，as a main mechanism of water driving in fractured tight sandstone reservoirs，imbibition is widely concerned. In view of the shortcomings of the current experimental research of imbibition，taking Chang8 reservoir of Wuqi area in Ordos Basin as target，the characteristics of the reservoir and the main influence factors of imbibition were analyzed by using low-temperature nitrogen adsorption，high pressure mercury injection and Amott methods，as well as nuclear magnetic resonance（NMR）technology. The experimental results show that as a water-wet reservoir，the formation is dominant by narrow slit-like pores with micro-and mesopore size. The throat is scattered and the reservoir belongs to fine throat and micro-fine pore type. Among the main factors which affect recovery efficiency of the imbibition，reservoir quality and maximum pore throat radius have positive correlation with the recovery efficiency of the imbibition，and specific surface area has negative correlation with the recovery efficiency. The increase of relative wettability index and the decrease of interfacial tension are favorable to the process of imbibition. So imbibition is obvious in hydrophilic tight sandstone reservoir with good pore structure and pore-throat connectivity，and imbibition after the hydraulic fracturing will play a positive role in the development of reservoir.