Loan words originate from the contact between languages and cultures. When a civilization and a culture of a country enter other country, a language enters that country along with them, too, and there are some characteristics in the above process. Loan word have the phonetic characteristics of the Korean language, since loan words are phonetically assimilated into Korean as they enter it, the original pronunciation of a foreign language is not maintained. Furthermore, the sound which doesn`t exist in Korean changes into sound that is the closest to Korean. Loan words contain the morphologic characteristic of korea. The verbs and adjectives of long words come to be necessarily attached with the suffixes such as "~(do or does~)" to be used. Loan words have a trait in which they transform into the proper meaning of Korean, in quality. Madamme means a wife, or a married la요 in French, but it means a landlady of a bar or a coffee shop in Korean. However, one of the important characteristics of loan words is that their word form is unstable. Contents and condense are used as loan words in Korean, the persons using contents say that they are the word because English pronunciation is the closest. The orthography of loan words has been established for the unification of word form because the word form of loan words is unstable. The orthography of loan words regulates that the already firmly rooted loan words are to be approved as they are, and that those which have not deeply rooted or newly those which come newly are to be transcribed in accordance with the orthography. At this time with the unification ahead of us, there are a lot of controversies that we should restore and develop out language and writing as the speech of one country and language of on nation. The orthography of loan words was adopted as a way of achieving the above objective. We are going to have an opportunity ti think about the orthography of the loan words in the age of the unification by comparing the basic principles of the orthography of the current loan words of South Korea and North Korea, and the orthography of loan words of South Korea and North Korea. Languages change all the time. However, since Korea has been divided for 50 years, the language of the nation shows that is has changed too much. Before our common national language changes further, South Korea and North Korea should exchange lots of data and their scholars will have to sit face to face and study this problem. Unless this task is positively promoted, the cultural unification will not be realized even if the territory is unified.