The purpose of this study is to provide implications for the development of textbooks according to the 2022 revised Korean language curriculum by selecting the contents of grammar education from the perspective of accuracy and effectiveness based on the learner’s understanding and use of time expression. The results of analyzing the contents of time expression education covered in the curriculum and textbooks confirmed that the contents of education needed to be detailed from the perspective of accuracy and the contents of education needed to added based on the perspective of effectiveness. The results of analyzing the learner’s understanding and use of time expression demonstrated the possibility of learning semantic functions of various time expressions, the possibility of inquiry based on the intuition of the native speaker, and the necessity of elaborating educational contents. In terms of accuracy, the educational content was selected in three categories: ‘attention to language forms’, ‘exploring various semantic functions of time expression’, ‘correcting writing using time expression accurately’. In terms of effectiveness the educational content was selected in two categories: ‘understanding time expression as a semantic resource’ and ‘reading and writing considering the effect of choosing time expression’.