Forest carbon pool plays an important role in the global carbon cycle. In order to understand the temporal and spatial dynamics of carbon density of forest vegetation and its influencing factors in Zhongtiao Mountains region of Shanxi Province, we quantitatively studied the carbon density of forest vegetation and the contribution of each driving factor to the spatial distribution of carbon density by using stochastic forest and structural equation model based on the data of national forest resources continuous inventory from 2005 to 2015. The results showed that: (1) The carbon density and carbon storage of forest vegetation in Zhongtiao Mountains in 2005, 2010 and 2015 were 24.87, 26.56, 31.42 Mg C/hm² and 15.89, 16.00, 20.15 Tg C, respectively, which showed a continuous increasing trend with an average annual growth rate of 2.63% and 2.68%, respectively. (2) The spatial distribution characteristics of vegetation carbon density were as follows: high (> 100 Mg C/hm²) and medium-high (60~100 Mg C/hm²) carbon density plots were mainly distributed in the central and southwest of Zhongtiao Mountains, while low carbon density plots (< 60 Mg C/hm²) were mainly distributed in the northeast. (3) Stand age and average annual rainfall were two important driving factors affecting the spatial pattern of vegetation carbon density in the study area. The direct positive effect of stand age on carbon density was the most significant, and average annual rainfall affected the spatial distribution pattern of carbon density through an indirect effect on stand factors.