Knowledge about Korean language History(KLH) is not only ‘inert knowledge’ about Korean language of past period but also ‘active knowledge’ which contributes full understanding the present-day Korean language and is valuable in Korean language education. KLH is very helpful in teaching letters, phonics, grammar, and vocabulary of the Korean language. Especially KLH serves to reduce foreign student’s difficulties caused by preconceptions that the Korean language has many exceptional and irregular linguistic phenomena. KLH makes many learning materials understanding that seem to require simple memorials. Furthermore KLH helps foreign students to understand Korean traditional culture well. Hence Korean language teachers need to understand this role of KLH in Korean language Education. (Hannam University)