〔Abstract〕 Objective Observe the abnormal detection rate of EEG in patients with mental illness who have takenantipsychotics for a long time, analyze its influencing factors, and propose preventive measures. Methods From June 2020 to December 2020, 256 patients who were hospitalized in Quanzhou Third Hospital who took antipsychotic drugs for a long time were examined by EEG, and the abnormal rate was counted; and different types of drugs and different age groups were observed. , The abnormal rate of EEG of patients with different medication time, and analyze the risk factors of abnormal EEG. Results 154 (60.16%) of 256 patients had EEG abnormalities, of which mild abnormalities were the most common clinically, and severe abnormalities were the least common. Among different types of drugs, clozapine users have the highest rate of abnormal EEG; among different age groups, the abnormal rate of EEG is higher than that of 60 years old. Conclusion The main influencing factors for abnormal EEG in patients taking antipsychotics for a long time are age > 60 years old and long-term use of clozapine. Therefore, it is necessary to choose drugs reasonably according to the age of patients in clinical practice, and try to choose drugs with smaller EEG levels. And closely monitor the patient's condition changes, and appropriately adjust or optimize the treatment plan.