Background <p>Besides learning theoretical knowledge in class, participating in extracurricular activities is vital to students' life development. Interpersonal trust is the basis for university students to establish a good social network. However, there is little discussion on the mechanism analysis that affects university students' participation in the second classroom.</p> Methods <p>To explore the impact of interpersonal trust on university students' participation in extracurricular activities, this study uses self-acceptance and self-esteem as mediating variables to make it a complete chain mediation model. Through a sample survey of university students, the chain mediation model is used to analyze the data.</p> Results <p>The results show that interpersonal trust, self-acceptance, and self-esteem significantly and positively impact university students' participation in extracurricular activities. In the chain mediation model, interpersonal trust positively affects university students’ second-classroom participation through the sequential mediators of self-acceptance and self-esteem. This hypothesized pathway was statistically supported by robust model fit indices, including Akaike’s Information Criterion (AIC) and Bayesian Information Criterion (BIC), derived from structural equation modeling (SEM).</p> Conclusion <p>Universities should create an excellent interpersonal trust environment for students and cultivate their self-acceptance and self-esteem. Improving students' participation in the second classroom is conducive to promoting university students' physical and mental health and all-around development.</p>