This study is to emphasize the importance of writing a sentence in a paragraph level as well as in a sentential level. Chapter 2 examined the necessity of the sentence writing education and then investigated what kind of grammar knowledge can be categorized as an education content in the sentence writing. Chapter 3 categorized the paragraph writing assignments of Korean native speakers and Korean learners into morphological element of sentence structure, agreement and word order between the sentence components and connection between the sentences for comparative analysis. As a result, it is observed that the Korean learners showed lots of morphological errors of sentence layer and experienced difficulty in the part of agreement and word order between the sentence components. Lastly, there were lots of unnatural sentences which are irrelevant to the overall subject in the connection between the sentences in a paragraph. It was found through discussion that sentence writing education for the Korean native speaker and Korean learners should be found. For the Korean learners, education for sentential levels accuracy and sentence education which can strengthen cohesion and coherence of paragraph levels are required. This can be done through connection between sentence and paragraph. (Seoul National University)