Objective To investigate the effects of community-based dietary intervention on type 2 diabetes mellitus. Methods One hundred and eighty-seven patients with confirmed type 2 diabetes mellitus were selected from a community in Shanghai, and were randomly assigned to intervention group (n＝95) and control group (n＝92). Patients in intervention group received dietary intervention and health education for 6 month under the guidance of community doctors, while those in control group did not. The condition of dietary control, knowledge of dietary, parameters of physical examinations, serum glucose and serum lipid were compared before and after intervention between two groups. Results Compared with those before intervention, the rate of favorable dietary control and awareness of dietary knowledge significantly increased after intervention in intervention group (P<0.05), the waist hip ratio and serum triglyceride significantly decreased (P<0.05), the fasting plasma glucose (FPG) and 2 h postprandial glucose (PG2h) significantly decreased, and were significantly lower than FPG and  PG2h of control group (P<0.05). Conclusion Community-based dietary intervention has some effects on the control of type 2 diabetes mellitus.