The process of schooling and students’ sense of belonging toschool affect their education achievement quite a lot. The mechanismof school activities and teachers’ behavior to students’ achievement isunder development. The former researches show that the sense ofschool belonging may play as a mediating factor between psychologydemands and obvious behaviors for early adolescents. This researchtries to conduct a model to figure out the mediation effect of schoolbelonging among school activities, teacher behaviors, and learningmotivation on academic achievement. In the research the SEM andcorrelation analysis are used to structure the hall model and estimatethe parameters. The research uses the junior high school students’data from the second wave Taiwan Education Panel Survey (TEPS)collected in 2003, and the sample size is 13,247. The result showsthat: (1) The students with positive feeling about teacher instructionand school activities tend to have higher sense of belonging to schooland learning motivation as well as better academic achievement. (2)Students’ anxiety has negative effect on their sense of belonging, butit proves to be positive on their motivation and achievement. (3) Thelearning motivation has positive effect on the achievement. (4) Themediation effect of school belonging is significant between schoolactivities, teacher behaviors and learning motivation. (5) The fitnessindex of the fixed model is acceptable, and the R square of hall modelis approximately 40. The research offers several concretesuggestions for teaching and school administration.