This research is a series of studies to find out the differences between onomatopoeia and mimetic word in Korean which examined each inherent phonological characteristic with comparing phonological differences composing onomatopoeia and mimetic word. Main results are as follows. First, more mimetic words are composed in Korean than onomatopoeia with 962 onomatopoeias and 3,441 mimetic words in typical Korean. Second, letters high frequently appearing in anlaut of onomatopoeia is in order of ‘vowel-ㄸ- ㄷ-ㄲ-ㅌ’ and mimetic word is in order of ‘vowel-ㅂ-ㅅ-ㄲ’. Third, ‘plosive’ appears more frequently in onomatopoeia than mimetic word in anlaut. Four, the most onomatopoeia ends with ‘ㄱ, ㅇ’ in auslaut final consonant. Mimetic word ends with ‘ㄴ, ㅅ, ㅇ’ relatively higher than onomatopoeia. Five, onomatopoeia shows large difference in general vocabulary than mimetic word phonologically.