With the development of College teaching and learning, some students majoring in mathematics have switched to using electronic devices to take photos instead of notes for recording. The purpose of this research is to explore the causes of this phenomenon. Research on this phenomenon can help improve students' learning and teachers' teaching in class. The research method used in this study is the interview method and interviewees are the undergraduates majoring in mathematics who have the habit of taking photos in class. The conclusions drawn from this study are as follows: (1) Taking photos is not satisfactory for learning. (2) The phenomenon can be attributed to the following factors: In terms of students, firstly, their learning concept is utilitarian and their learning motivation is weak. Secondly, some students are lazy about taking notes on non-exam content. Thirdly, some students have difficulty understanding the knowledge in class. Lastly, taking notes by hand is not organized. In terms of teachers, their lectures are too fast and illogical. In other aspects, taking photos has the advantage of clarity and convenience. Furthermore, students who take photos will subconsciously motivate other students to take photos in class. Based on the above analysis, in order to improve this phenomenon, it is suggested to improve students' note-taking ability, change students' learning concepts and improve teachers' information-based teaching level.