This paper aims to compare the desciptions on irregular conjugation verbs in `Korean Orthography`(Han-geul Ma-tsum-beop) and in textbooks on Korean grammar, with the intention of finding out the mutual influences afterwards. It also aims to appreciate the aims and functions of `school grammar` in the korean contexts. In chapter 2, the author has inspected that before the draft for the unification of Korean spelling(1933) have been made, how researchers described irregular conjugation verbs and inflections in Korean, and found the the first who mentioned about irregular conjugation verbs is An Hwak. In chapter 3, we examined how the irregular conjugation verbs have been treated in Korean Grammar books. In chapter 4, we summarized the changes in the descriptions on irregular conjugation verbs in the 5 revised versions of the draft for the unification of Korean spelling. In chapter 5, the author mentioned two problematic phenomena which should be reflected in the revision of the draft in 1988 version, but not included considered. In chapter 6, we emphasized the importance of grammar education in the school, especially the educations on the irregular conjugation verbs, not only they reflect synchronic phenomena but also they are one of the important elements to understand and usage of Korean Language.