Abstract: Objective:To investigate the Epstein-Barr virus(EBV) infection condition in hospitalized children from kunming city of Yunnan province,and related clinical popular distribution characteristics of disease spectrum.Methods:The clinical data of children suspected with EBV infection,the EBV nucleic acid positive cases identified using PCR fluorescence method,were retrospectively analyzed.Results:Among 547 blood samples,97 cases with positive EBV nucleic acid were detected,the detection rate of which was 17.73%,which included 56 males(57.73%) and 41 females(42.27%).The mean age of all cases was(4.60±2.84) years,and the pre-school children(0 to 6 years old) in 76 cases(78.35%) were found.The clinical symptoms of children infected with EBV was various.The upper respiratory tract infection symptoms(including fever,cough and lymph node enlargement) were the first symptoms of the EB V infection,and the pneumonia,bronchitis,infectious mononucleosis and pharyngitis were the clinical manifestations,which was accompanied by liver and spleen enlargement,rash,liver and heart muscle function damage.The combined pathogen infection in 71 cases were identified,which included mycoplasma pneumoniae infection in 19 cases(19.59%),typhoid and paratyphoid infection in 18 cases(18.56%),Japanese encephalitis virus infection in 17 cases(17.53%),parainfluenza infection in 8 cases(8.25%),intestinal virus infection in 2 cases(2.06%),other viruses in 7 cases(7.22%) and co-infection in 47 cases(42.27%).The difference of the detection rate in different seasons was not statstically significant(P>0.05).Conclusions:EBV infection is one of the most important pathogen of respiratory tract infection in hospitalized children in Kunming region,the disaese can occure in each season,and the mixture infection with other pathogen is common.