The invention relates to the field of preparation of cyclic urea compounds, particularly to a method for preparing 1-(2-ethoxyl)-2-imidazolone by using CO2 as a raw material. 1-(2-ethoxyl)-2-imidazolone is obtained through a reaction of CO2 and ethanolamine. Compared with a conventional technology for preparing 1-(2-ethoxyl)-2-imidazolone, the method disclosed by the invention has the following advantages: (1) a synthetic method is scientific to design, an execution route is concise and reliable, and the method is suitable for industrial production; (2) required raw materials are low in toxicity, are cheap and are easy to obtain, so that the method conforms to the trend of green chemical development; (3) a catalyst is used in the reaction process, the catalytic activity is high, and the product yield is higher; (4) from the view of resources, the CO2 is a safe non-toxic rich carbon resource, and a reaction product, namely water, does not cause pressure to the environment.