This paper reviewed the critical point of discussions on integrated curriculum theory between liberal arts and natural sciences to develop the national curriculum standards in Korean language teaching. To achieve this development, I discussed the national curriculum standards’ integrating method from the 1st National Curriculum to the 2011 National Curriculum and argued directions of integrated curriculum development that are based on chronological characteristics of language development. I investigated the meaning of antagonism between differentiation and integration in language development, as well as suggested 37 integrating methods that are useful for Korean language teaching. Also, I analyzed in details about the subjects crossing integration based on the theme and the areas crossing integration based on the text. Looking at both existing national curriculum stands and many new ideas, I criticized the contents’ frameworks of integrated curriculum in Korean language teaching. Finally, I argued necessity of chronological structuralization of language curriculum based on characteristics of language development. I could add a new criteria on the theory of Korean education curriculum and suggest some important focuses, such as chronological integration, in the curriculum development of year 2015.