Soil nitrogen-fixing bacterial communities play a key role in nitrogen recycling in phyllostachys edulis plantations forest soils. However, so far little has been reported on changes in structure and abundance of the nitrogen-fixing bacterial community in Phyllostachys edulis plantations with age of cultivation. In this study, soil samples were collected from the topsoil (0~20 cm) layers of four Phyllostachys edulis plantations different in cultivation history (5 a, 9 a, 15 a and 18 a, respectively) and a Pinus massoniana plantation similar in ecological background (as control, CK). Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and real-time fluorescent quantitative PCR (qPCR) were employed to characterize changes in structure and abundance of the soil nitrogen-fixing bacterial communities in the soils, separately. Factors affecting structure of the nitrogen-fixing bacterial communities in soils were analysed using the redundancy analysis method. Results show that soil pH and contents of readily available potassium, available phosphorus, organic matter and ammonium nitrogen in the soil increased greatly 5 years after the transformation of Pinus massoniana stand into Phyllostachys edulis stand, but then decreased gradually and leveled off with the plantation going on. Shannon and richness indices and nifHgene copies of the soil nitrogen-fixing bacterial communities show similar trends. Sequencing of DGGE bands reveals that in the soils under Phyllostachys edulis plantations, the N₂-fixing bacteria are all unculturable azotobacteria that are quite similar to Bradyrhizobium sp. Redundancy analysis (RDA) shows that age of cultivation clearly affected structure of the soil nitrogen-fixing bacterial communities in Phyllostachys edulis plantations and the community structures in the soils after 5 a and 9 a of cultivation differed sharply from that in control. However, differences between the plots of 15 a and 18 a and control were not so significant. Besides, soil readily available potassium, available phosphorus, organic matter and pH were the main factors affecting nitrogen-fixing bacterial community in soils under Phyllostachys edulis plantations. Therefore, changes in soil fertility induced by long-term Phyllostachys edulis plantations can potentially influence diversity of the soil nitrogen-fixing bacteria and alter their community structure.