Objective: This study aims to examine the mediating effect of career maturity on the relationship between positive psychological capital and job identity among preservice early childhood teachers. Methods: A total of 253 preservice early childhood teachers participated in a survey measuring positive psychological capital, job identity, and career maturity. The collected data were analyzed using IBM SPSS Statistics ver. 25 and the PROCESS Macro 4.2 to conduct descriptive statistics, correlation analysis, and mediation analysis. Results: First, preservice early childhood teachers demonstrated generally high levels of positive psychological capital, job identity, and career maturity. Second, positive psychological capital, job identity, and career maturity were all positively correlated. Specifically, higher positive psychological capital was associated with higher job identity, and greater career maturity was also linked to stronger job identity. Additionally, career maturity was found to partially mediate the relationship between positive psychological capital and job identity. Conclusion/Implications: The findings suggest that early childhood teacher training institutions should develop and implement programs that enhance positive psychological capital and job identity in order to foster career maturity among preservice early childhood teachers.