In this study one of the poems of Koryeo dynasty, Isanggok is divided into 10 lines as Hyangga in Silla dynasty and interpreted like this. When snow fell heavily on a mountain hut like drizzle On the frosty winding path of tight frost columns crunching noise. Each eaves and brushwood doors For the hardly frozen shape my heart wave roughly. I`m nesting the hut with missing my lover gone away Would he come to here through the stupefied path? Who should perish soon and fall into hell for being hit by lightning Will I walk another mountain path with leaving my lover? Was it a promise saying this or that? Oh, sweetheart, it`s a promise living together forever. Isanggok is a poem that shows obscenity from illicit love affair. The secret place of two lovers, desolation and dreariness of the path toward that place, lyric I`s feelings like the shape of frozen path, fear for suffering a punishment due to guilt, lament for destiny of perish of body, and the promise to keep at last etc., the pitiful emotions of female speaker are expressed on the poem. Therefore the speaker of the poem may be a prostitute of a red-light district not a faithful widow. We should estimate this poem`s lyric value highly. Because the delicate sensual descriptions of poetic situation is eminent and the emotions of waiting and pledge for lover is appealing. This poem is a high level lyric in that the emotional concreteness is in accord with poetic situation. On the other hand, it is necessary to set a place of this poem on the stream of Korean lyric history. Through this study Isanggok is appeared as a poem to be constructed with the same poetic structure of 10 lines Hyangga of Silla dynasty. The mixed foots turned from 3 foots, insertion of zest-phrases and alteration of interjection in last two lines etc. is a change on the lyric history. But Isanggok follows 10 lines Hyangga in the basic form and meaning structure. It is significant in that this poem expresses the pitiful love feelings which are deficient in existing works of Hyangga. The change in stream of Korean lyric history is distinguished in the rhyme change from 3 foots to 4 foots. The poems of Koryeo dynasty, Koyreo-Gayo having 3 foots jointly with Hyangga make a intermediate role in change to 4 foots lyrics like Shijo and Gasa. Some works of Koyreo-Gayo show the rhyme features of transitional period, and Isanggok is one of the cases. In short, Isanggok has significances in the side of pure lyric features and the side of place in the stream of lyric history.