This study aims to examine the semantics of prefixes and their semantic relatedness, based on the meanings of native Korean prefixes. First of all, the feature of [state] or [property] can be assigned to each prefix, based on its meaning, particularly whether it makes the stativeness or the property of the individual prefix clear. When a prefix has the two meanings, the two features can be assigned simultaneously. Secondly, the feature of [+degree] can be assigned to a prefix, when it adds the degreeness to the following base, or gives an emphatic meaning to the base. However, when it adds a new meaning to the following base, the feature of [-degree] is assumed to the prefix. Third, an item with [+degree] can be divided into an item with [below the standard] and one with [above the standard], based on whether it is above the specific standard or not. The feature of [-degree] adds new meanings to the following base, and can be subdivided into [activity], [directedness], [relatedness], [productivity], [visuality] and [temporality], by its specific meaning. Otherwise, it is treated as an item with [otherness]. Literatures up till now have been concentrated upon the meaning of the individual prefix, and further upon the classifcation of them, based on their semantic similarity. However this study is focused on the the semantic relatedness among prefixes and on the overall and systematic aspects of them.