Objectives: Research focused on examine the mediating effect of positive psychological capital as an protective factor and self control on the relationship between smartphone addiction and adaptation to school life of elementary school students. Methods: We surveyed 575 people in three elementary schools in Gyeonggi-do regarding smartphone addiction, positive psychological capital, self-control, and school life adaptation. Of these, 527 questionnaires were analyzed. The collected data were correlated, multi-returned, hierarchical regression, and path analysis using the SPSS 23.0, AMOS 23 statistical programs. Results: First, the correlation analysis of related factors indicated a significant correlation between smartphone addiction and school life adaptation, positive psychological capital and self-control. Second, the self-efficiency, hope and optimism in the subcomponents of positive psychological capital and the pursuit of long-term satisfaction among the subcomponents of self-control had a positive effect on school life adaptation, and the immediate pursuit of satisfaction had a negative effect. Third, positive psychological capital and self-control showed significant mediated effects in the effects of smartphone addiction on school life adaptation. Fourth, route analysis showed that smartphone addiction did not have a significant direct impact on school life adaptation, and only gave significant indirect effects by means of positive psychological capital and self-control. Conclusions: it is necessary to strengthen self-control and expand the level of positive psychological capital through education and programs to minimize the negative effects of smartphone addiction on school life.