Prejudice is the negative judgment formed by individuals who base on incorrect or insufficient information and preconceived opinions about others. Prejudice will make people have one?sided or wrong cognition about a group when it generalizes into a group. This study explains the psychological mechanism of doctor?patient prejudice from three perspectives of negative stereotype， expectation discrepancy and attribution bias， to discuss the negative influence of prejudice on doctor?patient relationship， suggesting some ways combining social reality to reduce the prejudice between doctors and patients.