To explore the correlation between respiratory syncytial virus (RSV) A, B subgroups and specific antibodies IgM, IgG and IgA in hospitalized children, we screened 50 cases of RSV-RNA positive patients through throat swab among hospitalized children by means of fluorescent quantitative polymerase chain reaction (FQ-PCR). The genotyping was performed according to the nucleotide sequence of the gene encoding G protein of RSV, and a single tube multiplex semi nested PCR primers was designed for A, B subgroups. RSV specific antibodies IgM, IgG and IgA in the serum were detected by ELISA. This study found that there is no relationship between any subgroups of the virus and the three isotypes tested of the specific antibody. The time took for the onset of IgM was the same for infection by subgroup A and B alone or in combination. IgA was produced earliest and did not exist alone; the longer the clinical symptoms persist, the greater the probability of coexistence of the three isotypic antibodies.