Mental health literacy (MHL) is important for improving mental health. In a narrow sense, it refers to the knowledge and beliefs about mental disorders which aid their recognition, management or prevention. In a broad sense, it refers to the comprehensive use of mental health knowledge, skills and attitudes to maintain and promote mental health. MHL is often measured by Vignette case questionnaire, and unidimensional or multi-dimensional scales. Interventions including social campaigns, school education, self-service application and Mental Health First Aid training can effectively improve MHL. Elements of MHL, including psychological health knowledge, mental disorder recognition, emotional regulation, anti-stigma, and help-seeking attitude etc, are positively related to mental health. Future research can be carried out in such aspects as constructing the MHL evaluation system, exploring the mechanism of its influence, expanding the coverage of research, and strengthening empirical intervention research.