Objective:　To analyze the clinicopathological characteristics of bladder cancer with diabetes mellitus, and to provide reference for the clinical diagnosis and treatment of bladder cancer. Methods:　The data of patients with primary urothelial bladder cancer treated in urology department of Xijing Hospital from January 2014 to February 2019 were collected retrospectively. Patients with diabetes mellitus were classified as diabetic group (DM group) and patients without diabetes mellitus were classified as non-diabetic group (No-DM group). The clinical and pathological characteristics of the patients were analyzed. Results:　The age and the proportion of hypertension in DM group were higher than that in No-DM group, with statistical significance (P<0.05). There was no significant difference between the two groups in the constituent ratio of clinical characteristics such as gender, education level, smoking, drinking, body mass index (BMI), complaint symptoms, course of disease, urinary tract infection and hyperplasia of prostate (P>0.05). There was significant difference in the constituent ratio of tumor grade between the two groups (P=0.007), and the proportion of high grade carcinoma in DM group (52.8%) was higher than that in No-DM group (34.2%). There was no significant difference in tumor stage, tumor number and tumor size between the two groups (P>0.05). Multivariate logistic regression analysis showed that age (P<0.05), course of disease (P=0.045) and diabetes mellitus (P=0.026) were independent influencing factors of cancer grade, while gender, smoking, drinking, hypertension and BMI had no statistical significance in malignant grade of bladder cancer (P>0.05). Conclusion:　Age, course of disease and diabetes mellitus were independent factors influencing the pathological grade of bladder cancer. We should pay attention to the diagnosis and treatment characteristics of bladder cancer patients with diabetes mellitus, which has a certain positive significance for improving its prognosis.