Objective To investigate the relationship of non-verbal facial expression features and aggression risk of patients with severe mental disorders. Methods This study is a cross-sectional study. The study was carried out in 15 community hospitals in Beijing from September to December in 2019. A total of 30 patients with severe mental disorders who had aggressive behavior and met the International Classification of Diseases-10 diagnostic criteria were included. Modified Overt Aggression Scale（ MOAS）， Patient Health Questionnaire 9-items（ PHQ-9） and Generalized Anxiety Disorder Scales 7-items（ GAD-7） were applied to evaluate aggression risk， depression and anxiety respectively. Openface extracted 5 action units（ AU）： AU4 （brow lowerer），AU5（ upper lid raiser）， AU7（ lid tightener）， AU20（ lip stretcher）， and AU23（ lip tightener）. The intensity and duration of each AU were calculated， and the correlation between AU index and the total score of MOAS was studied using partial correlation analysis. Results Among the duration of AU indexes， AU5 （r=0.395， P=0.037）， AU20（ r=0.414， P=0.029）， AU23（ r=0.407， P=0.032） were positively correlated with the total score of MOAS. The intensity AU indexes showed that AU20（ r=0.557， P=0.002） and AU23（ r=0.466， P=0.013） were positively correlated with the total score of MOAS. Conclusions Facial expression features could be helpful to identify aggression risk of patients with severe mental disorders.