Abstract: Objective This essay was to analyze the epidemiological features and epidemic factors in outburst of pharyngo-conjunctival fever resulted from type III adenovirus．Methods Descriptive epi- demiological analysis and case control study were adopted tO investigate the course of onsets and transmis-sion factors of pharygno-conjunctival fever taking place in kindergartens，accompanied by nucleic acid I-dentification of isolated virus using throat swabs and determination of antibodies against virus by collect-ing serum．Results From 21st of June tO 19th of July in 2004，258 of 349 young children in kinder-gartens fell ill．With an attack rate of 73.9％．The cases were distributed among different grades while had no significant difference between classes．The epidemiological curve took on a single peak．Among children under day-care service，the attack rate of children who participated in swimming sports was ob-viously higher than those who did not (X2=28.96，P<0.001)and increased along with the frequency of swimming．Experimental results indicated that 10 pharnyx swabs of 27 patients were determined as aden-ovirus positive by PCR (37％)，for 6 of which genetic sequencing was applied besides analysis of genetic se-quence (29obp) acquired，demonstrating a homology of 97％ with type III adenovirus SO that the ampli-fication product of PCR can be regarded as type III adenovirns．In the meanwhile，other pathogens such as respiratory syncytial virus and type I parainfluenza virus were also detected．Conclusion The principal pathogen of this epidemic is type III adenovirus，and pharyngo-conjunctival fever breaks out mainly through water and contact transmission when young children are playing in the swimming pool of kinder-gartens，combining with many other pathogenic infections．