Objective To discuss the combinations of multimorbidity of chronic diseases in the elderly in communities and the related influence factors.Methods The data of 19185 elderly people aged at 65 and over were collected through cluster random sampling method;the multimorbidity was analyzed and according to the number of chronic diseases,the outcome variables were divided into 4 groups:group 0,group 1,group 2 and group 3 +;multinomial logistic regression was applied in analyzing the influence factors of multimorbidity.Results The prevalence rate of multimorbidity in the elderly was 22.26 ％,including 16.02％ of the elderly with any 2 kinds of chronic diseases,the most prevalent combination ranged as follows:hypertension + diabetes (8.14％),hypertension + coronary heart disease (6.35 ％) and hypertension + fatty liver (5.20％),and including 5.18％ of the elderly with any 3 kinds of chronic diseases,the most common combination ranged as follows:hypertension + coronary heart disease + diabetes (2.03％),hypertension + diabetes + fatty liver (1.75％) and hypertension + coronary heart disease + fatty liver (1.02％);the results of multinomial logistic regression analysis indicated that senile age,widowhood,overweight or obesity and smoking quitting were the risk factors for multirmorbidity.Conelusions The prevalence rate of multimorbidity in the elderly in Shanghai communities is high,the most common multimorbidity are the combinations with any 2 or 3 diseases among hypertension,diabetes,coronary heart disease and fatty liver;senile age,widowhood,overweight or obesity and smoking quitting may be the risk factors for multimorbidity;proper measures of health management should be taken and appropriate distribution of medical resources should be made.