In the field of psychiatry, studies on circadian rhythms are increasing. This research trend is based on the emerging evidence on the relationship between circadian rhythm and pathophysiology and prognosis of psychiatric disorders.As performing the research on this area, the difficulty in analyzing large amount of data that are sequentially collected according to time change exists. In order to properly analyze the data in research on the circadian rhythm, it is necessary to effectively apply analysis methods of time series data. Therefore, this review aimed to summarize the analysis methods of circadian rhythms that show time series data. Understanding the analysis method of circadian rhythm will be useful for utilizing clinical data in the form of a time series data in the smart medical field in the future.