Objective To test the reliability and validity of the rating scale of social function deficit due to mental disorders (SSFD-MD). Methods 1003 cases with mental disability evaluation were tested by SSFDMD. At sametime, 100 cases of 1003 cases were test-retested and back to back tested by two examiners. 300 cases of 1003 cases also were tested by social disability screening schedule( SDSS),scale of social function for psychosis inpatients(SSPI),global assessment function(GAF) ,the brief psychiatric rating scale(BPRS) ,WH0 disability assessment scale Ⅱ (WHO-DASⅡ ), adult rating scale of mentally disabled ( ARSMD) and rating scale for extrapyramidal side effects (RSESE). Results ①The Cronbach's α coefficients of the total score and all dimensions of SSFD-MD were more than 0.90. The test-retest reliability ranged from 0.67～0. 83 ,and the scorer reliability were 0. 87～0.97. ②The correlations between item scores ranged from 0.46 ～0.74(P＜0.01). The correlations between the factor scores and the total scores ranged from 0.73～0.87(P＜0.01). To extract five full-scale principal components after orthogonal rotation to maximize variance,the cumulative total variance explained was 82.25%.There were highly correlations between SSFD-MD and SDSS.SSPI and GAF,respectively ( r = 0. 71,0.72 and 0. 78). There were moderate correlations between SSFD-MD and BPRS WHO-DAS II ARSMD,respectively(0.62,0. 50 and 0.46). There was a low correlations between SSFD-MD and RSESE ( r = 0.22) ,but all correlations were significant(P＜0.01). Conclusion SSFD-MD has acceptable psychometrics properties on reliability and validity.