Long-term poor glycemic control of diabetes can affect the nervous system and produce a variety of neurological complications. The effects of diabetes on the nervous system include the following: First, the central nervous system, diabetes will aggravate the occurrence and development of atherosclerosis, atherosclerosis of the cerebral vessels will easily lead to insufficient blood supply to the cerebral arteries, and even cerebral infarction, affecting the function of the nervous system. Second, affect the peripheral nerves, poor blood sugar control of diabetic patients, easy to appear the end of the limbs of numbness, pins and needles, as well as gloves, glove-like sensation. Diabetes affects the cranial nerves. The most commonly affected nerves are the abducens nerve, the facial nerve and the oculogyric nerve, resulting in the corresponding symptoms. The vegetative nerves include sympathetic and parasympathetic nerves, which are widely distributed in the human body and govern the functions of multiple systems. Therefore, long-term poor glycemic control of diabetes may lead to gastrointestinal phytonuropathy, cardiac phytonuropathy, phytonuropathy of the sweat glands of the skin and diabetic bladder, etc., resulting in the corresponding clinical symptoms.