Objective: To analyze 4 years changes in the cost of diabetes patients and their composition, provide reference for the system design, cost control, health resource use and reduction of economical burden. Methods: We analyzed the medical record data of a tertiary hospital in Nanjing during 2013-2016, and the patients were divided into different groups according to year, age, medical insurance type and number of complication diseases. The medical costs for patients was statistically described and analysis in variance. Results: From 2013 to 2016, diabetes patients number increased, the hospitalization cost increased too, and the ratio of drug cost decreased. The hospitalization cost in the elderly over 60 years group was significantly higher than that of the other groups. Different kinds of social security groups had significant differences of hospitalization cost. The self-paying group showed the lowest hospitalization cost than other groups. The more complication diseases, the higher hospitalization cost. Conclusion: Hospitalization cost of diabetes patients is associated with age, medical insurance type, and complication disease. Great efforts should be taken into improve the patients’survival quality and reduce the economic burden by standard treatment, through enhancing prevention and control and designing reasonable system.