Abstract: 　Objective　To explore the epidemiology of different subgroups of respiratory syncytial virus (RSV) in hospitalized children with acute respiratory infections in Suzhou. Methods RSV antigen in nasopharyngeal secretions specimens obtained from 42 208 hospitalized children with acute respiratory infections from January 2006 to December 2012 were detected using direct immunofluorescence assay. RT-PCR was used to differentiate subgroups A and B of RSV from the positive samples which were randomly selected in the epidemic season of different years. Results RSV infection had a seasonal trend. The peak season of RSV occurred between November and following year’s March and the detection rate of RSV was low between May and September. There was difference in RSV positive rates of peak seasons among different years from 2006 to 2012 (χ²=280.09，P<0.01). In 398 RSV antigen positive samples obtained from peak seasons of different years, 80.15% (319/398) were differentiated as subgroup A and 15.83% (63/398) were subgroup B except 16 samples (4.02%). There was significant difference in distribution of RSV subgroups in peak seasons among different years (P<0.01). Subgroup A of RSV was prevalent in most years. Both subgroup A and B were prevalent in peak season of 2008～2009 with lowest positive rate of RSV. In 2009～2010, subgroup B was prevalent. Conclusions From 2006 to 2012 in Suzhou area, the RSV detection rates in the first four prevalent seasons present an increase trend every other year and then sustain a high prevalence in the following two prevalent seasons. Subgroup A of RSV was the predominant pathogen in hospitalized children with acute respiratory infections.