To study the effects of different C/N ratios on the decomposition characteristic of Chinese fir (Cunninghamia lanceolata, CL) litters, in this study, the CL litters with different C/N ratios by adding exogenous nitrogen were placed in the CL plantation with two management measures including undergrowth vegetation preservation and undergrowth vegetation removal by decomposition bag method, and its bacterial community structure was determined at 300 days. The results are as follows: within a certain range, the reduction of initial C/N ratio was beneficial to the decomposition and the improvement of bacterial community diversity of CL litters, while the excessively low initial C/N ratio had an inhibitory effect. Compared with undergrowth vegetation removal, the undergrowth vegetation preservation was more beneficial to the decomposition and the improvement of bacterial community diversity of CL litters, but the inhibition effect of the initial C/N ratio of 20.3 on the decomposition of CL litters was more obvious in the undergrowth vegetation preservation plantation. At the level of phylum, Proteobacteria, Actinomycetes and Planctomycetes were the main dominant species in CL litters; On the genus level, the relative abundance of Bradyrhizobium, Acidothermus and Singulisphaera were high in the CL litters. The bacterial community structure among CL litters with different treatments, as well as the relative abundance of various bacteria belonging to Proteobacteria, Actinomycetes and Acidobacteria and so on, were significantly different. At the level of phylum classification, the correlation between the C/N ratio of CL litters and the relative abundance of major bacterial populations was the highest, and the correlation between the C/P ratio and the structural variation of bacterial communities was the highest; At the level of genus classification, the correlation between total carbon content, C/N ratio and total potassium content of CL litters and relative abundance of major bacterial populations was the highest, and the correlation between total potassium content and the structural variation of bacterial communities was the highest. The reduction of the initial C/N ratio changed the bacterial community structure of CL litters, thus affecting the decomposition of CL litters.