Respiratory tract infection has its 90% origins in virus among children and youngs. These virus which induce respiratory tract infection range over 200 types of more than 10 categories of 7 families. In the last few year, there have been outbreak of virus respiratory tract infection frequently. Viruses known are mutating, and new virus are generate. Study on molecular epidemiology of respiratory viruses and identification of new virus species are key issues for the study of infectious disease. In this research several new respiratory viruses (NL63, HKU-1, hMPV, HBoV) and major respiratoru viruses were investigated in molecular epidemiology, and a VP1-U protein was expressed and purified.Human bocavirus (HBoV) is a non-enveloped,single-stranded DNA virus. In 2005, the virus was first detected by Allander from samples of children with respiratory infection. General studies from its biotaxis, molecular biology, analysis of phylogenetic tree and epidemiology showed that HBoV has basic characters of parvovirus and has similar structural feature with the members of the other known Boca viruses of parvovirus, which testified that HboV is the new member of Boca viruses. HboV can result in upper or lower respiratory infection of children, even severe respiratory diseases. There are resports about Boca viruses all over the world, but there is still little knowledge about this kind of virus. This article reviews this virus from its viral biological feature, epidemic feature and diagnosis in order to attract some attention for this virus. The identification of new virus species is a key issue for the tudy of infectious disease but is technically very difficult. We developed a system for large-scale molecular virus screening of clinical samples ased on host DNA depletion, random PCR amplification, large-scale sequencing, and bioinfor- matics. The first experiments detected seven human virus species without the use of any specific reagent. Among the detected viruses were one coronavirus and one parvovirus, both of which were at that time uncharacterized. The parvovirus, provisionally named human bocavirus.Multiple studies have confirmed the presence of HBoV in respiratory tract samples of children world-wide. HBoV has recently also been detected in blood and fecal samples. Most studies so far have studied virus prevalence, and only a few reports provide data regarding the linkage of HBoV to disease. These reports indicate that HBoV infection is indeed associated with acute respiratory tract symptoms resulting in frequent detection of low load HBoV carriage. This phenomenon has complicated the use of PCR diagnostics, which has been the only available diagnostic method. Development of alternative diagnostic strategies will be important for future studies of HBoV and its association with disease.Creation of detectable method by molecular biology: whole virus nucleic acid were extracted from NPA samples of children who were hospitalized because of respiratory tract infection and RT, the interested conservative sequences were argmented by PCR. If the longth of electrophoresis band is in accord with interested sequence, it was though that interested virus was in the sample. Investigation of epidemiology of HBoV: research on epidemiology of HBoV in given group showed that bronchiolitis, pneumonia, bronchopneumonia probably were linked to HBoV, and incidence was about 4.37%.The project use the method of PCR, HBoV NS1 genes were detected by throat swab in 1007 children with acute respiratory infection from January to May 2008. 8 products of positive cases were selected trabantly to detect the sequence, analyze the clinical data, and the HBoV sequences were compared with the sequeces of GenBank. There are 29 samples were confirmed to be infected by HboV in 1007 children. The positiv rato is 4.37% (44/1007). The max detection rate of HBoV is in the children with bronchiolitis and acute bronchitis. Detection rate are 8.70% (2/23) and 5.71% (2/35), in broncho- pneumonia is 4.79% (38/794), in acute upper respiratory infection is 1.29% (2/155). Principal clinical situation is cough and gasp. 34.14% of the patients have diarrhea. 54.55% of the patients have a fever, 95.12% of them have dry rales and/or bubbling. Laboratory examination shows that the percentage of lymphocytes increase in complete blood. 87.80% of the chest radiograph is shown infiltrates. The youngest child infected by HboV is19 days. The oldest is 5 years old. The peak age of infecting HBoV is 7-12 months. The infection rate is 52.3% (23/44). The homology of HBoV between 10 cases of ChangChun Children’s Hospital and that of Genbank is 99%-100%.Conclusion: Children of ChangChun area who were infected with acute respiratory infection concerned with HBoV. HBoV cause respiratory passage symptom, most of it is lower respiratory tract inflammation; most age of onset is younger than 1 year.