Abstract: In order to study the causes of coal miners’ unsafe behavior in the informal organization perspective, group dynamics theory was introduced, and the informal organization factors affecting coal miners’ behavior were identified with the method of literature review and field research. An informal organization scale was developed and questionnaires were distributed, SPSS25.0 was used to analyze the questionnaire data. The structural equation model（ＳＥＭ） was used to construct the path analysis model of coal miners’ unsafe behavior, and the influence of informal organizational factors on unsafe behavior were analyzed. The results show that group cohesion and self-safety behavior of coal miners positively affect the unsafe behavior of coal miners, and group cohesion positively affects miners’ self-safety behavior. Group pressure and referential effect negatively affect the unsafe behavior of coal miners, and group pressure positively affects inter-miner reference effect.