The increasing carbon dioxide (CO2) emissions have a serious impact on climate change. As one of the most important technologies for achieving carbon emission reduction, CO2 capture has attracted widespread attention from academia and industry. Chemical absorption is an effective and suitable CO2 capture technology for low CO2 partial pressure areas, such as flue gas. The commonly used flue gas CO2 capture method in industry is the monoethanolamine (MEA) absorption method, which has the advantages of mature technology, simple operation, and high absorption rate, but the disadvantages are high energy consumption for regeneration and easy degradation of absorbent. The development of an efficient, low-energy, and environmentally-friendly absorbent has been a difficult and hot research topic in this field. As a class of green solvents, ionic liquids (ILs) provide a new opportunity for CO2 capture due to their tunable structure, fast reaction rate, and high absorption capacity, and have become a promising solvent for CO2 capture. However, the low CO2 absorption capacity of conventional ILs and the high cost and viscosity of functionalized ILs have limited the industrial application of ILs in CO2 capture. ILs mixed with organic amine are a potential CO2 capture solvent, which can not only maintain high absorption capacity but also avoid the problem of viscosity and high cost. In this work, a superbase IL (1,8-diazabicyclo[5,4,0]undec-7-ene imidazole, [HDBU][Im]) was mixed with MEA to obtain IL blending solvents to improve the CO2 absorption capacity of the absorbent and reduce the viscosity of the solvent after absorption. The effects of IL concentration, absorption temperature, and CO2 partial pressure on the CO2 capture performance of the IL blending solvents were investigated, and the physical properties, such as density and viscosity of the IL blending solvents under different CO2 absorption capacities were analyzed. The results showed that 30wt% MEA+10wt% [HDBU][Im] had a better absorption capacity, and at the temperature of 40℃, the CO2 absorption capacity was 0.1453 g CO2/g solvent, and the viscosities before and after CO2 absorption were 2.312 and 4.303 mPa?s, respectively, which were significantly lower than those of IL absorbents. Therefore, it is a promising absorbent for CO2 capture.