The intermediary effect interval of the preschool teachers’ competence characteristics → positive psychological capital → the subjective well-being of the preschool teachers is (0.23—0.55), does not contain 0, and the effect amount is 0.35. The competency characteristics of preschool teachers → The direct effect interval of subjective well-being of preschool teachers is (0.05—0.36), excluding 0, and the effect quantity is 0.20, indicating that positive psychological capital as a mediator variable has the characteristics of preschool teachers and the subjective well-being of preschool teachers. Partial mediating effect, the ratio of mediating effect to total effect is 64.01%.