This research focuses on Reaction-Paper as a clue to understand students’ learning in a lesson, and examines how to utilize the descriptive contents of Reaction-Paper. As a result of examining nine precedent studies that try to understand students’ learning by using their descriptive contents of Reaction-Paper, three are suggested. First, precedent studies can be classified into [the fact report type], [the qualitative interpretation type] and [the category analysis type], but each type has its own weakness. Therefore, a new analytical method that enables us to understand students’ learning “specifically” and “systematically” is needed. Second, research to analyze various aspects of students’ learning organically is needed. And finally, research to correlate Reaction-Paper with other related data is needed.