In order to research on the impact of imbibition effects, mechanisms and the correlation factors of the tight oil cores, the experimental devices of tight core imbibiton were established. The experiments of oil-water imbibition of tight sandstone were carried out. The effects of temperature, pressure and surfactant on the oil-water imbibition in compacted core were studied. The curves of imbibition efficiency versus time, characteristic points of curve and the influential factor of imbibition were analyzed. The imbibition law and characteristics of tight sandstone core were obtained. The results showed that the effect of imbibition was mainly occurred on the surface layer of the tight oil core. The temperature had a large effect on the second stage of imbibition. The oilwater imbibiton efficiency of the single tight oil core is about 10%, which is about 25% under the formation conditions.