The main purpose of this study is to explore the current situation of positive belief, emotional management of elementary school regular grade teachers and the classroom management effectiveness in Tainan County. The study uses the survey method. There were 526 subjects for elementary school regular grade teachers in Tainan County. The instrument was ”Positive Belief, Emotional Management of Elementary School Regular Grade Teachers and the Classroom Management Effectiveness Inventory”. Data was analyzed by descriptive statistics, t test, ANOVA, and regression analysis. The main findings of this study are as follows: (1) The degrees of positive belief, emotional management of elementary school regular grade teachers and the classroom management effectiveness are at upper middle levels. (2) Positive belief and emotional management can significantly predict the classroom management effectiveness. (3) Emotional management can act partial mediation effects between positive belief and the classroom management effectiveness. According to the research findings, this author proposes several suggestions for the reference of school administration, elementary school teachers, and future studies.