16S rDNA-PCR-DGGE was used to analyze the bacterial community dynamic changes in rhizosphere soil infected by cucumber Fusarium wilt. There are 5 rhizosphere soil samples， including pre-planting soil， pre-inoculation soil， diseased cucumber and healthy cucumber after inoculation， not inoculated as the control. Total DNA was directly extracted and amplified with F338-GC and R518 primers targeting the 16S rDNA
V3. The amplified were analyzed by DGGE analysis. The result revealed that there was a high diversity of bacterial community compositions among different tested soil samples. Fusarium caused a great bacterial species and number changes in rhizosphere soil， of which Rhodococcus phenolicus， Clostridium sp. and 3 uncultured bacteria increased， another 2 uncultured bacteria reduced after inoculation.