Objective To analyze the clinical features of adult patients with dengue fever complicated with central nervous system(CNS) injury, and to provide evidence for the diagnosis and treatment of dengue fever complicated with CNS injury. Method The clinical database of dengue fever in our hospital was used to select adult patients with dengue fever complicated with CNS injury, and they were divided into non-elderly and elderly groups according to age <60 years. The general information, clinical manifestations, laboratory examination, cerebrospinal fluid examination, and cytokines detection results were compared and analyzed between the two groups. Result 84 cases of dengue fever complicated with CNS injury were included, 27 were non-elderly (32.1%), and 57 were elderly (67.9) %, with a median age of 72.5 years, 45 were male (53.6%), Of the 84 patients, the main forms of manifestations were encephalopathy (34 cases, 40.5%), lacunar infarction (15 cases, 17.9%), cerebral ischemia (11 cases, 13.1%), and encephalitis (11 cases, 13.1%). 72 cases (85.7%) were severe dengue, 86.2% of the patients were infected with dengue virus type 1. There were 64 cases (76.2%) of patients with underlying diseases, mainly hypertension (43 cases, 51.2%), diabetes (24 cases, 28.6%) and heart disease (20 cases, 23.8%). The clinical manifestations were mainly headache (36 cases, 42.9%), coma (36 cases, 42.9%), dizziness (29 cases, 34.5%), lethargy (23 cases, 27.4%), vomiting (18 cases, 21.4%), agitation/seizure (17 cases, 20.2%). 33 cases (39.3%) were found to have combined damage to other organs, 15 cases (17.9%) had serious bleeding in other parts of the body, and 54 cases (64.3%) showed signs of plasma leakage. The laboratory tests mainly showed a significant decrease in platelet and albumin levels, a significant increase in cytokine levels. Positive results for pathogenic examination of cerebrospinal fluid in 4 cases (22.2%). After treatment, 67 cases (79.8%) improved, while 17 cases (20.2%) deteriorated. The proportion of patients with underlying diseases, hypertension, and heart disease in the elderly group were significantly higher than that in the non-elderly group (P<0.05), and the proportion of patients with lethargy in the elderly group was significantly higher than that in the non-elderly group (35.1% vs 11.1%, P<0.05). There was no significant difference in prognosis between the two groups. Conclusion The majority of dengue fever patients with CNS injury are elderly, with a high proportion of combined with hypertension, diabetes and heart disease. Encephalopathy is the most common form. The manifestations are mainly headache, coma, lethargy, and dizziness, suggesting that it is necessary to be alert to the possibility of CNS injury when consciousness level changes, and early cerebrospinal fluid examination can help clarify the diagnosis.