Despite its extensive use and its historical background in the Western rhetoric, not only the definition of allegory but also the determination of its functions has been a matter of debate among the critics and rhetoricians. This problem is partly due to some commonalities and differences between allegory and other rhetorical figures, such as metaphor, symbol, emblem, irony, and so forth. As a result, the significance of allegory in different historical periods, according to the intellectual currents of the society, has undergone many ups and downs. For the first time, it was during the Romantic period that the rhetoricians studied the features and functions of allegory as compared to symbol, in order to distinguish the borders of these two terms and to provide a precise definition for each term by characterizing them. In fact, the modern conception of allegory is indebted to the Romantic commentators such as Goethe, Schelling, August Wilhelm Schlegel, and Coleridge. These rhetoricians made the first systematic effort to clarify and define the term “allegory”. On the same basis, this article presents a report on the functions and features of allegory among the Romanticists, most notably Goethe, Schelling, A.W. Schlegel and Coleridge.