In this study, the participants comprised 385 preschool teachers. The relationship among their emotional labor, Job Involvement, and psychological capital were examined using hierarchical regression analysis. In addition, whether psychological capital exerted a mediating effect on Job Involvement was investigated. The results show that "deep acting exerted" the strongest influence on Job Involvement in preschool teachers and that high psychological capital alleviated their emotional burden. Moreover, "self-efficacy" and "optimism" mitigated the need for psychological satisfaction of work in preschool teachers. In addition, "optimism" exerted a mediating effect on the relationship between emotional labor and Job Involvement in preschool teachers.