Abstract: School refusal is the phenomenon that the students can not go to school not because of their poverty or health problems, but of their psychological, emotional, physical and social reasons. In Europe and the United States the earliest studies on school refusal were conducted. In Japan the studies have been conducted for 50 years. This paper tries to track the evolutional process of the concept -- from "School Phobia", "School Refusal" to " Non School Attendance " in Japan. It also tries to illustrate the Japanese researchers’ studies about the reasons of school refusal from several respects such as family, school and society. It analyses students’ behavior mechanism such as separation anxiety, emotional disorders and poor family relations．Then it introduces Koizumi’ classification of school refusal used by the Ministry of Education of Japan as well. Finally it shows up the possible development of this phenomenon in China

Key words: school phobia, school refusal, non school attendance, concept evolution, behavior mechanism