【Objective】Moso bamboo (Phyllostachys heterocycla) is an important non-timber forest resource in subtropical China. Intensive bamboo forest management, beginning in the 1980s, has enormously increased the area of moso bamboo plantations and economic return for farmers. However, these long-term management practices, such as removal of understories and excessive application of nitrogen fertilizers combined with tillage, have already brought about some negative impacts, such as significantly altering soil microbial communities and increasing N₂ O emission, of which the latter possibly reflects changes in the population of denitrifying bacteria. To explore this possibility, investigations were made of abundance of denitrifying bacteria in moso bamboo plantations under long-term intensive management. 【Method】Soil samples were collected from the surface (0~20 cm) and subsurface (20~40 cm) soil layers of moso bamboo plantations receiving 0 (CK), 10, 15, 20 and 25 years of intensive management, for analysis of abundances of denitrifying communities (nirK-, nirS - and nosZ-denitrifiers). In addition with the aid of real-time quantitative PCR, and for analysis of soil physicochemical properties in an attempt to determine major factors that contribute the most to alteration of denitrifying bacteria in abundance. 【Result】It was found that the abundances of soil denitrifying bacteria in the moso bamboo plantations (1.45×10⁶～3.03×10⁸ copies•g^-1 dry soil) were generally higher than those reported for other ecosystems, except in the case of nirS in farmland. Abundances of the three functional genes in both soil layers increased or remained unchanged during the first 10 years of intensive management. With the exception of nirS in the surface soil, all three functional genes then decreased somewhat after either 15 or 20 years of intensive management. Eventually however, and with the exception of nosZ in the surface soil, abundances of the other genes recovered or even exceeded the level in control after 25 years of intensive management, indicating a resistence of denitrifying bacteria to disturbance caused by intensive management practices. The abundances of nirS and nosZ in the surface soil samples were significantly higher than those in the subsurface soil samples, but nirK showed an a reverse trend. This phenomenon possibly reflects the observed decreases in pH and dissolved organic carbon excreted by bamboo root in the subsurface soil. Correlation analysis between soil physicochemical properties and functional genes reveals that the denitrifying genes, nirK, nirS, and nosZ, were positively related to total N, available P, and organic carbon in the surface soils. Additionally, nosZ was also positively related to C/N. However, in the subsurface soils, all the three denitrification genes as a group were significantly and positively related to organic carbon. Redundancy analysis demonstrates that the impacts of intensive management significantly on denitrifying bacteria were main reflected in the comprehensive effects of soil nitrogen and organic carbon on activities and functioning of the bacteria. 【Conclusion】In summary, all the findings in this study indicate that long-term intensive management substantially alters both soil physicochemical properties and associated denitrifying bacterial communities. But the effect varies with soil layer, which means that depth of the soil is also a key factor affecting composition of the denitrifying bacterial community. Compared to some other ecosystems, the intensively managed moso bamboo plantations are relatively higher in abundance of denitrifying bacterial functional genes. Active participation of these bacteria in nitrogen recycling leads to increased emission of N₂O. Therefore, it is suggested that growers should use slow-release N fertilizers to reduce the concentration of ammonium nitrogen in the soil solution, thus encourage plant to absorb ammonium before it is nitrified. This strategy is believed to be able to decrease production of nitrate and hence denitrification and N₂O emissions.