Purpose: Principal leadership is an important external environmental factor that affects and alleviates teachers' job burnout. The purpose of this paper is to explore the deep internal mechanisms of the influence of principal transformational leadership on teacher job burnout in the context of Chinese teachers. Design/methodology/approach: A cluster sampling method was used to conduct a questionnaire survey on 990 elementary school teachers in 14 primary schools in Beijing. This study uses a structural equation model to analyze the chain intermediary effect of social-emotional competence and the student-teacher relationship between transformational leadership and teachers' job burnout. Findings: The results reveal that transformational leadership has a significant negative predictive effect on teachers' job burnout; this kind of leadership affects teachers' job burnout through a chain intermediary effect of social and emotional competence and student-teacher relationship. Originality/value: This research has discovered that teacher burnout is the result of the interaction of external environmental and individual internal factors. Transformational leadership, as an external environmental factor, positively predicts the internal social-emotional competence of the teacher, and then the teacher's internal social-emotional competence positively predicts the external student-teacher relationship. Finally, the teacher-student relationship of the external environment negatively predicts the job burnout of internal individual teachers.