This paper examined the literacy that is the basis of learning Korean language ability as a part of the basic discussion on learning Korean, the core of KSL education. In other words, it explored the literature developmental aspects of Korean native speaker children and KSL child learners through literature review and discuss the key issues in the literacy education of KSL child learners. A KSL child learner is a bilingual learner who has already developed a certain level of ability to use a native language. For mother tongue speakers, early childhood is basically the period of spoken language and the beginning of basic literacy development. During this period, the Korean reading ability starts from the level of recognizing a word as a whole unit, and develops to the level of connecting the phonemes of the word with the sound of the syllable unit The following points are suggested in the literacy education of KSL child learners. First, the curriculum should be differentiated according to the age at which KSL learners start to study Korean. Many studies showed that learners in the higher grades show higher achievement than learners in the lower grades of elementary school. Second, the level of achievement should be different considering the level of development of KSL learners. The current curriculum aims to improve the level of Korean proficiency to TOPIK level 4 within one year regardless of grade. Third, it is necessary to differentiate educational contents according to the Korean acquisition patterns of KSL learners. As shown in the results of the study, for example, KSL learners in 3rd and 4th grades show the lack of vocabulary such as lack of production vocabulary and lack of understanding of homonyms, which is an important factor to lower the text comprehension.