Teachers' ability and quality of education are highly correlated. In order to improve the quality of education, we should focus on improving the quality and ability of teachers. Rather than relying on individual teachers' educational experience or experience, quality education should be continually discussed through systematic and scientific analysis. The purpose of this study is to explore the details of the class analysis needed to improve the quality of Korean language teaching. For this purpose, we collected and analyzed the class observation report and examined the detailed items necessary for class observation and analysis and teacher recognition of each item. In this study, we tried to analyze the data using the qualitative research program Nvivo 11 and tried to approach the case study to interpret the collected observation report. As a result of the analysis, the major factors of class observation were teacher factor, learner factor, and class environment factor. Teacher factor was the most frequent item in class observation. Among them, teaching method factor was 74 coding and 61% frequency.