At present，the supercritical CO2 assisted fracturing technology has become one of the effective methods for the development of tight oil reservoirs. In the process of fracturing，the energy storage and flowback effect of fracturing fluid has become one of the focuses in recent years. In order to quantitatively evaluate the energy storage in the formation and fluid flowback efficiency during the supercritical CO2 displacement，this paper independently designed an experimental apparatus to investigate the efficiency of energy storage and flowback under different displacement modes of the supercritical CO2. The changes of mean pressure and flowback efficiencies of the core system under continuous gas injection，continuous water injection and alternate water and gas injection were compared by the laboratory experiment under reservoir temperature and pressure，and the gas injection slug with alternating water and gas injection was also optimized. The results show that the supercritical CO2 as a preflush can increase the energy storage efficiency of subsequent injection of slippery water.The injected supercritical CO2 expands the volume of crude oil and irreducible water，and the degree of expansion is greatly affected by the dissolved amount of supercritical CO2，but less affected by the core system pressure. The displacement method of injecting supercritical CO2 followed by injecting slippage water shows the best energy increasing efficiency，which can achieve supercritical CO2 storage，and the highest flowback efficiency of slippage water and oil recovery. From the perspective of the energy storage and fluid flowback efficiencies，the best volume of the supercritical CO2 slug is 0.5 PV.