There are provided an ionic liquid having ether group(s) in which a copper(I) compound is included, a method for preparing the same, and a method for removing traces amounts of acetylene-based hydrocarbon compounds included in olefin by absorption or extraction using the same. When the disclosed solution is used, oxidation of Cu(I) to Cu(II) is prevented since CuX is stabilized by the ionic liquid. Thus, selective removal efficiency of acetylenic compounds is improved greatly while the removal performance is retained for a long period of time. Further, since the solution according to the present disclosure is applicable as an extractant as well as an absorbent, the associated operation is simple and apparatus cost can be decreased.