Objective To investigate the clinical characteristics, auxiliary examination, treatment and prognosis of patients with anti contactin associated protein- related 2( CASPR2) antibody associated encephalitis. Methods The clinical data of 5 consecutive patients with anti CASPR2 antibody associated encephalitis admitted to the Department of Neurology, the Third People's Hospital of Huai'an from March 2018 to March 2020 were retrospectively analyzed and the literature was reviewed. Results The clinical manifestations were limbic system symptoms in 5 cases( 3 cases of epilepsy, 1 case of abnormal mental behavior, 1 case of cognitive impairment with abnormal mental behavior); 1 case had limbic system symptoms complicated with Morvans syndrome; 2 cases had increased peripheral nerve excitability and autonomic nerve dysfunction; 2 cases had obvious MRI abnormalities; 1 case had malignant tumor; All the 5 cases had insomnia. All patients were recieved the immunotherapy . The patients were followed up for 3-14 months( median follow-up time was 9 months). The symptoms of 4 cases were improved obviously, except the case with tumor. Conclusions The main manifestations of anti CASPR2 antibody associated encephalitis were limbic system symptoms, increased peripheral nerve excitability, autonomic nerve dysfunction and insomnia. When the above manifestations appear, it is necessary to consider the disease and make early diagnosis through antibody detection and other detection. Immunotherapy and anti epilepsy symptomatic treatment is suggested. Most of the prognosis is good, except case combined with tumor which is not good. Some patients may relapse and may develop new antibodies.