The purpose of this paper is to investigate phonological characteristics in children’s poems of Mokwol Park on the basis of syllable structure. That is, I divide syllables of poem into onset, nuclear, and coda, then observe which phonemes are used frequently. The study about children’s poems of Mokwol Park sufficiently obtains a substantial argument in view of the literary theory. However, it is insufficient for the argument of linguistic method. Poetry is based upon the relationship of similarity among sounds. Sounds perceived as similar to one another create acceptable rhythm pairs. Because sounds are hierarchically arranged in languages, patterns in poetry can reveal the priority order within this hierarchy. So, with respect to the phonological patterns of Korean, I have analyzed all of Mokwol Park’s works. At last I found the priority order about children’s poems of Mokwol Park within sound hierarchy. Most common are syllables with onset and no coda pairs. With respect to acoustic features, the most frequent syllable utilize the [+sonorant] feature. This pattern remains consistent over time.