The purpose of this paper is to classify Korean adverbs. The one classification is sentence adverb and component adverb. The other is free adverb and constraint adverb. Korean adverb categorize conjunctive, mood, time, location, manner, degree, symbol, negative. Conjunctive adverb categorize ‘and’, ‘but’, cause-and-effect, selection. Mood adverb can divide supposition, emphasis, amplification, doubt, reason, change, assumption, conviction, negation. Time adverb can classify past, present, future, moment, continue. Location adverb can classify standstill, move. Manner adverb can classify frequency, manner. Degree adverb can divide 4 grade. Symbol adverb’s meaning can be show by subject and verb. Negation adverb are composed by ‘can not’ and ‘will not’, ‘can not’ indicate ability and ‘will not’ indicate will. The adverb’s meaning exhibit it’s meaning by itself, not depend on syntax and other components.