Patients with diabetes are prone to concurrent infection. The mechanism of concurrent infection is related to factors such as hyperglycemia and weakened defense function. The infections of patients with diabetes include general and special infections. General infection includes infections in the respiratory system, urinary system, hepatobiliary system, and skin mucosa. Meanwhile, special infection includes invasive otitis externa, nasal mucormycosis, necrotizing fasciitis, and emphysema infection. Patients with special infections also have a higher mortality rate than those with general ones. Complicated infection with diabetes is difficult to treat and has poor prognosis. Therefore, a patient requires active treatment once infected with this infection.