The purpose of this article is to explore the guidance of college students' mental health and the construction of social environment based on ideological education, so as to improve the level of college students' mental health. Firstly, the universality, types, and causes of college students' mental health problems are analyzed, and the seriousness and urgency of college students' mental health problems are pointed out. Then, it analyzes the influence of social environment on college students' mental health and points out the importance and influencing factors of social environment on college students' mental health. Finally, it puts forward the measures of mental health guidance and social environment construction for college students based on ideological education, including establishing mental health service mechanism, strengthening social environment construction, and promoting the publicity of college students' mental health knowledge.