Through investigating the hospital admission and hospital discharge of vagrant mental patients in Xi-aoshan Hospital from January 2011 to December 2015 , the present study found that there existed some ethical di-lemmas including the risk ofdiagnosing mental disorder but actually not, lack of the guarantee of patients' rights and interests and supervision mechanism without guardian, long-term retention in the wards, and so on. It is sug-gested to establish right protection and supervision committee for vagrant mental patients, reduce the misdiagnosis ofdiagnosing mental disorder but actually not through the error correction mechanism, ensure proper treatment and care, create retention way, protect the basic rights of the vagrant mental patients, reduce mental disability, avoid to stray again, so as to perfect the social management system.