An ionic liquid solvent and gas purification method using the same are provided. The ionic liquid solvent consists of a main absorbent, a regulator for the main absorbent, an auxiliary absorbent, an activator, an antioxidant and water. The ionic liquid involves a low synthetic cost, low viscosity and high absorption capacity, and can be easily regenerated and recycled. The method, compared with traditional processes, has advantages such as a greater absorption capability and lower operation cost.