With the continuous expansion of higher vocational education, students in vocational colleges face clear changes in learning methods, living environments, and interpersonal communication. Because of this, problems of social adaptation have become more obvious. Social Adaptation Disorders not only affect students’ learning involvement and interpersonal development, but also have a long-term influence on their mental health. Among vocational college students, peer relationships are one of the most important sources of social support in daily life. They play an important role in reducing social adaptation pressure, adjusting emotional experience, and promoting mental health. Based on this background, this study takes vocational college students as the research group. After reviewing theories related to Social Adaptation Disorders, peer relationships, and mental health, this study builds a theoretical framework to explain how peer relationships affect the mental health of students with Social Adaptation Disorders. Empirical methods are used to test the research hypotheses. The results show that peer support and peer acceptance have a clear positive effect on the mental health of these students, while negative peer interactions may increase their psychological stress. These findings help people better understand the relationship between social adaptation and mental health among vocational college students. They also provide a theoretical basis for mental health education and intervention programs in vocational colleges that focus on peer relationships.