Disclosed is a method for preparing lactide by using a solvent. According to the method, since an ionic liquid is used as a solvent in a second step in the course of preparing lactide, it is possible to secure mobility of the resulting reactant, and decrease a reaction temperature. In addition, the ionic liquid absorbs moisture generated during the reaction, and thus prevents degradation of lactide which is susceptible to moisture. Furthermore, to the present method allows for the preparation of lactide successively through the continuous supply of lactic acid oligomers. Because the use of an ionic liquid minimizes the contamination of a reactive group with by-products, the use of a solvent for reactor washing is unnecessary. Further, owing to a high boiling point of the ionic liquid, the ionic liquid can be easily harvested and recycled.