This study investigated the mental health of vocational college students in Shandong Province based on the DASS-21 scale, focusing on significant differences across demographic variables. The results revealed that mental health differed significantly in terms of gender, age, grade, major, family economic status, parents’ educational attainment, family structure, and frequency of communication with family (p < 0.05). The findings indicate that social support and psychological resilience play crucial roles in influencing the mental health of vocational college students. Students with different demographic characteristics demonstrated diverse levels of mental health. This study provides empirical evidence to support mental health education and intervention programs in vocational colleges.