Objective: To study the effect of community intervention on mental health of patients with type 2 diabetes mellitus (DM) Method:Two communities in a city of Shandong province were chosen as intervention community and control community respectively after an epidemiological investigation of diabetes mellitus in 1997 After four years intervention, a case-control study was done by assessing mental status with SAS (self-rating anxiety scale), SDS (self-rating depression scale) and SSRS (social support rating scale) Result:Compared with baseline levels, after intervention for 4 years, the SAS score, SDS score and SSRS score (including subject score and object score) of patients in intervention community improved significantly, while the counterparts of patients in control community had no improvement But patients in intervention community still had poorer results than health controls By adjustment of the potential confounding effect of age, sex and occupations, diabetes mellitus still had influence on anxiety, depression and social support with ORs of 1 41, 1 69 and 0 69 respectively Multivariable stepwise analysis showed that, suffering from other chronic diseases was risk factor for mental health of diabetes patients, and the higher the education level, the better results of intervention Conclusion:The DM community intervention program improves mental health of patients significantly, but patients still have poorer mental health than healthy control Education level and suffering from other chronic disease are main factors having influence on effects of the intervention