Abstract: In order to specify the effect of temperature on the imbibition efficiency in tight reservoirs after dense cut volume fracturing, imbibition mechanism experiments on the natural tight oil reservoir cores of Lucaogou Formation of Jimusar Sag were carried out under different temperature and pressure conditions by using the HTHP imbibition experimental apparatus for tight cores. The experimental results of imbibition and oil displacement showed that the imbibition efficiency increases as the temperature increases, the imbibition rate also accelerates with the increasing temperature, and the time required for imbibition reaction is reduced. When the experimental temperature is higher than the in-situ tight oil reservoir temperature of Jimusar Sag, the temperature increase has a minor effect on the imbibition efficiency. Correspondingly, when the experimental temperature is lower than the reservoir temperature, the lower the temperature, the greater its influence on the imbibition efficiency. There is a positive correlation between the imbibition amount and the saturated oil mass per unit area at different temperature conditions. The results indicated that temperature change has a great effect on the imbibition and oil displacement of the Lucaogou tight oil reservoirs in the Jimusar Sag. Therefore, the cold damage to the formation caused by the fracture fluid should be controlled as much as possible in the volume fracturing of tight oil reservoirs.