Principals’ emotional intelligence could influence their transformational leadership, and affect school organizational effectiveness and teachers’ occupational well-being. Teachers’ emotional labor could mediate the relationship among emotional intelligence, transformational leadership, school organizational effectiveness and occupational well-being. Thus, this study’s purposes are: 1. Explore the effect of principals’ emotional intelligence on principals’ transformational leadership. 2. Clarify the direct effect of principals ’ emotional intelligence and transformational leadership on teachers ’occupational well-being and organizational effectiveness. 3. Further understand the mediating effect of teachers’ emotional regulation on principals’ emotional intelligence and transformational leadership, teachers’ occupational well-being and school organizational effectiveness. This study is conducted through questionnaire to collect opinions of junior high school teachers, adopt CFA to confirm the statistic data, using analysis of variance to test the differences between groups and within groups. Through HLM analysis and polynomial-level regression analysis, researchers test the relationships in the model. This study has five conclusions: 1. There is positive relationship between principles’ emotional intelligence and school organizational effectiveness. 2. The better principles’ transformational leadership and emotional intelligence; the better teachers’ occupational well-being will be. 3. There is positive relationship between principles’ emotional intelligence and transformational leadership. 4. Teachers’ emotional regulation will cause mediating effect on the relationship of principles’ emotional intelligence and transformational leadership to teachers’ occupational well-being. 5. Teachers’ emotional regulation will cause mediating effect on the relationship of principles’ emotional intelligence and transformational leadership to school organizational effectiveness.