Objective:To explore the relationships among perceived social constraints, social participation, as well as anxiety and depression in first stroke patients, and to further analyze the mediating effect of social participation on these variables.Methods:A total of 216 first stroke patients in the Department of Neurology of Affiliated Hospital of Qingdao University from April to December 2020 were recruited by convenience sampling and investigated by general information questionnaire, Social Constraints Scale (SCS), Chinese version of Impact on Participation and Autonomy Questionaire (IPA-C) and Hospital Anxiety and Depression Scale (HADS).Results:The total score of SCS, IPA-C, depression and anxiety were 33.49 ± 6.81, 43.42 ± 9.62, 8.05 ± 4.15 and 8.61 ± 2.59. Social constraints were positively correlated with social participation as well as anxiety ( r=0.644, 0.383, both P<0.05). Social constraints were positively correlated with social participation as well as depression ( r=0.482, 0.371, both P<0.05). The quality of social participation partially mediated the relationship between social constraints and anxiety (intermediary effect was 0.119), and also partially mediated the relationship between social constraints and depression (intermediary effect was 0.270). Conclusions:First stroke patients experience high level of social constraints, low quality of social participation and severe anxiety and depression. Social constraints can affect anxiety and depression through social participation. Medical staff should build a good environment to meet the needs of stroke patients of social participation, help patients to establish a correct psychological coping style, reduce patients' avoidance of social participation due to perceived constraints and exclusion, and thus promote the mental health of patients.