This study aims to explore the relationship between college students’ volunteer service experience, self-efficacy and moral identity and college students’ Public Service Motivation(PSM). It provides empirical insights for improving PSM among college students and informs educational programs and policies that can promote a more active and service-oriented youth population. A questionnaire-based study was conducted among college students in Jiangxi and Hunan provinces, using the Volunteer Service Experience Scale, Self-Efficacy Scale, Moral Identity Scale, and Public Service Motivation Scale. Data were collected from March to May 2023, with participants selected through stratified random sampling to ensure diverse representation from various universities and academic disciplines. A total of 1,400 students participated, with 1,344 valid responses. (1) Volunteer service experience positively influences college students’ Public Service Motivation. (2) Self-efficacy partially mediates the relationship between volunteer service experience and PSM. (3) Moral identity also partially mediates the relationship between volunteer service experience and PSM. (4) Both self-efficacy and moral identity function as chain mediators in the pathway from volunteer service experience to PSM. Self-efficacy and moral identity serve as chain mediators between college students’ volunteer service experience and their Public Service Motivation (PSM). Volunteer service experience positively impacts PSM, with self-efficacy and moral identity facilitating this relationship. Specifically, self-efficacy enhances PSM, while moral identity further strengthens this connection.