Objective To investigate the prevalence status of overweight and obesity among the middle‐aged and elderly pop‐ulations in southwest area and their influence factors .Methods By adopting the stratified cluster sampling method ,the mode of the questionnaire investigation combined with the physical examination was adopted to collect the effective data in 7 205 permanent resi‐dents aged 40-79 years old in cities and countries of Chongqing and Chengdu ,including the contents of age ,waistline ,hipline ,dias‐tolic blood pressure ,heart rate ,postprandial blood sugar ,triglyceride ,exercise frequency ,uric acid ,etc .The prevalence rates of over‐weight and obesity among the middle‐aged and elderly populations in southwest area and their distribution characteristics in cities and countries ,and in male and female populations were described .The related influence factors of overweight and obesity were in‐vestigatedResults The prevalence rate of overweight was 35 .91% among the middle‐aged and elderly populations in southwest area (37 .02% for cities ,32 .92% for countries ,33 .84% for males and 37 .41% for females);the prevalence rate of obesity was 11 .40%(11 .13% for cities ,11 .40% for countries ,8 .94% for males and 12 .84% for females);among them ,the overweight rate in cities was higher than that in countries ,the overweight rate in females was higher than that in males .The obesity rate in females was higher than that in males(P<0 .01) ,the obesity rate had no difference between cities and countries(P>0 .05) .The multivariate re‐gression analysis showed that lack of exercise ,overweight or obesity family history were the risk factors of male overweight and o‐besity ,while the difference between cities and countries ,lack of exercise were the risk factors of female overweight and obesity .Con‐clusion The overweight and obesity rates among the middle‐aged and elderly populations in southwest area are high ,the body mass in nearly half of people exceeds the normal standard .Strengthening the overweight and obesity related health education in communi‐ties and restraining the serious trend of overweight in the population of this area have an important significance for the prevention and treatment of cardiovascular diseases .