Objective   To investigate the prevalence of diabetes mellitus (DM) and the beseline of the knowledge in middle-aged and elderly population (50-70 years old) for guidance of the future intervention and evaluation of the effect of intervention.

  Methods   A community-based sampling survey.

  Results   The overall prevalence of DM in the community heart disease, hyper-lipid and family history of diabetes but was not obviously correlated with history of hyper tension or coronary heart disease.The rate answ ering correctly the question "the diagnostic reference criteria for diabetes" was the lowest (2.94%) among the DM know ledge questions.The associated factors of the score of diabetes knowledge were age, sex, education, occupation, economy status, suffering status of diabetes, reading, watching TV or movies and physical exercise.The probability of prevalence of diabetes was related to family history of diabetes, hypertension, coronary heart disease, hyperlipid, physical exercise and cultural degree.

  Conclusion   In middle and old aged people, the prevalence rate of diabetes was high, but they hadn't paid more attention to it.There were also some feeble taches on knowledge of diabetes.All these provided good evidence for the future intervention programme and would direct the community health promotion strategies deeply.