The effect of long-term elevated CO2 (as open top chambers) on rhizosphere and bulk bacterial community structure in Pinus sylvestriformis seedlings field was investigated in July, August, and September. The bacterial communities were processed by Denaturing Gradient Gel Electrophoresis (DGGE) analysis of bacterial 16S rDNA fragments amplified by PCR (Polymerase Chain Reaction) from DNA extracted directly from soil. DGGE profiles from rhizosphere samples showed large changes in rhizosphere bacterial community under elevated CO2 compared to ambient except for that in September. For bulk samples, bacterial community structure changed when exposed to elevated CO2 in three months. With the exception of bulk samples in August, a similitude of bacterial communities structures existed between different elevated CO2 concentrations by analyzing UPGMA dendrogram based on Jaccard’s coefficient.