Objective To investigate the medical charge of in-patients with diabetes and its influencing factors for effective hospital costs controlling. Methods The inpatients with diabetes (the first diagnosis was diabetes; the first three ICD-10 codes of which were between E10 to E14) in Fifth Peoples' Hospital of Chengdu during January to September of 2014 were analyzed for their hospital costs with descriptive statistical method, ANOVA and multiple linear regression method. Statistical analysis was conducted by using SPSS 18.0 software. Results A total of 1 389 cases of diabetes were included. The median of total medical costs and daily costs were 4 554.45 yuan and 446.46 yuan, respectively. The differences of total medical costs and daily costs between diabetes patients with different amount of complications were statistically significant (P<0.001). The factors including age, the way of the medical expense, the number of complications, with acute complications, CCI score and the hospital-stay length were proved to be significantly correlated to total medical costs of diabetes inpatients (P<0.05). Conclusion Age, the way of the medical expense, the number of complications, with acute complications, CCI score and the hospital-stay length are influence factors of medical costs of diabetes inpatients.