Abstract: Objective To analyze the clinical characteristics,diagnosis and differential diagnosis of diabetes mellitus-chronic inflammatory demyelinating polyneuropathy.Methods The age of the four cases was between 37-58 years old when they visited us.The duration of type 2 diabetes mellitus was 3-9 years.The patients manifested the progressive weakness of limbs with sensory disturbance.Results The electrophysiological examination showed impairment of both axon and myelin.The CSF showed albuminocytolgoic dissociation in the 4 patients.Variant degree of involvement of H reflex and F wave was observed.Conclusions All four patients manifest obvious motor dysfunction.Though the decrease of nerve conduction velocity is the characteristic of demyelination,the albuminocytolgoic dissociation of CSF are important for the diagnosis