Although prosocial behavior has been regarded as a critical predictor of positive peer relationships and teacher-student relationships, more interventional studies are needed to more confidently determine causality. Dizi Gui instruction, a Confucian classical approach, was used in the current research as a prosocial behavior intervention to test whether it would improve Chinese adolescents' peer relationships and teacher-student relationships through the increase of prosocial behavior. Four classes of fifth grade students (N = 242, 118 males, 124 females) participated. The results showed that the Dizi Gui instruction effectively increased students' prosocial behavior, which in turn, improved their peer relationships and teacher-student relationships.