Microbial community composition in PCBs-contaminated paddy field soils was analyzed by PCR-DGGE.Impacts of PCBs and soil physico-chemical properties on soil microbial composition were investigated by canonical correspondence analysis.Results show that soil microbial community composition varied with soil PCBs level,and soils relatively higher in PCBs content (64.0～484.5 ng g^-1 dw) were quite close in community structure.Moreover,PCBs contamination affected more significantly (p<0.05) bacterial species composition in comparison with other soil physico-chemical factors such as available phosphorus,pH,organic matter,etc.,suggesting that under the stress of PCBs,the entire soil microbial community changed.In conclusion,PCBs pose a potential ecological risk to the microbial ecosystem in contaminated paddy soils.