Objective:develop a scale for the social function deficit due to mental disorders(SSFD-MD).Methods:The rating scale theoretical framework and item content of social function deficit due to mental disorders were establishedthrough reviews of literature,interviews with patients and their families and expert evaluation.And after item discrimination the scale was formed.More than 1,000 cases with mental disorders and mental disability,50 normal subjects and 50patients with physical disabilities were tested by the scale.Results:①The scores of the group of mental disorder of thefive subscales of “self care”,“family life”,“understanding exchange”,“interpersonal relation”,“social participation” andtotal score were significant higher than those of the other two groups(P＜0.01).②Different disease scores ranked from highto low as follows:organic mental disorders,schizophrenia,paranoid disorder,mood disorder with psychotic symptoms,mood disorders without psychotic symptoms,personality disorders,and neurotic disorders.There were significant differences among groups(P<0.01).③The compliance rate of the grades evaluated by SSFD-MD and evaluated by experts withGAF was 87%.These two methods of assessment showed no significant difference.Conclusion:The test results of SSFDMDare in line with the general clinical rules of mental illnesses and their impact on social functions;and SSFD-MD canreflect social function impairment in patients with mental disorders.