The purpose of this study was to examine differences between directly measured and parent-evaluated executive function in predicting children's academic achievement and social development, and to explore the mediating roles of peer status and social competence in the effects of executive function on social behavior. Patients and Methods: The study followed 106 first-grade children in an elementary school in China for one year. Regression and mediation analyses were conducted using SPSS 26.0 and AMOS 21.0 to test the hypotheses. Results: First, in a comparison of the predictive role of directly measured and parent-evaluated executive function, directly measured executive function played a more important role in predicting academic achievement, while parent-evaluated executive function played a greater role in predicting social development. Second, parent-evaluated executive function influenced social behavior primarily through social competence and peer status, with social competence playing a more significant mediating role than peer status. Conclusion: Compared with previous studies, the results of the present study provide more direct evidence for the relationship and differences between directly measured and parent-evaluated executive function, further suggesting that they have different efficacy and predictive goals, while the present study also describes the pathways through which executive function influences social behavior: the mediating role of peer status and social competence. This suggests that, on the one hand, educators or researchers need to choose appropriate measures of executive function for their own purposes and, on the other hand, in order to promote the development of children's social behavior, they need to focus on the development of children's executive function, social competence and peer relationships.