Abstract:The aim of this study was to analyze the clinical features of Japanese encephalitis(JE) in Chongqing city.Using the method of retrospective reserch to analyzing the clinical characteristics,who were diagnosed as JE by Children's Hospital of Chongqing Medical University during 2007~2010 years. Results showed that of the 303 JE cases,the ratio of male to female was 2.03:1.Children from 2 month to 15 years old infected epidemic encephalitis B,attacking time was between the July and the December,and 77 cases were in the July,207 cases were in the Aug,19 cases were in the Sep,and the ratio of unvaccination to vaccination was 8.7:1.All the cases distributed among 35 districts,180 cases (59.4%) were mild JE,100 cases (33.0%) were moderate JE and 23 cases (7.6%) were severe JE.The main clinical manifestation included fever(100.0%)、headache(37.0%)、vomiting(45.2%)、convulsion(70.6%) and consciousness disorders(85.2%).Positive rate of JEV-lgM in serum and in cerebrospinal fluid accounted for 44.61% and 79.21% respectively,98.1% with abnormal electroencephalogram,53.00% cases with abnormal cranial CT and 68.3% cases with abnormal cranial MR imaging.47.2% cases accompanied with different levels complications when they were in hospital,98.3% cases got better when they discharged from hospital and 5 cases died.It's concluded as follows:1.Most cases reported from the July to August in Chongqing city,all the cases lived in rural and most cases with unvaccination history.2.Mild JE was the major status,their symptoms included fever,convulsions and coma.3.The positive rate of JEV-lgM in cerebrospinal fluid was higher than in serum,most cases accompanied with abnormal EEG 、cranial CT and MR imaging,and got better when they discharged from hospital.