Many practices in afforestation and Ulmus lamellosa forest management were implemented for addressing the issues of tree species selection, planting regimes and development of structure. However, little is known about the ecological gradient and its relation with environment. We aimed to determine the factors controlling plant distribution and the importance of topography in determining local-scale spatial patterns of plants. The occurrence and distribution of plants were investigated on 60 plots in the Taiyue Mountain Reserve, Shanxi. Association types were classified by two-way indicator species analysis (TWINSPAN) and the relationship between the distribution and abundance of species and environmental gradients was analyzed by the canonical correspondence analysis (CCA) ordination method. Forward selection and Monte Carlo permutation tests were used to select the factors important in determining the plant distribution. The 60 survey plots were classified into seven groups characterized by the dominant tree species. The results of CCA ordination reflected the relationship between association structure and selected environmental variables. The distribution of 60 plots in CCA ordination was consistent with the results of TWINSPAN. Forward selection and Monte Carlo testing suggested that slope, slope position and elevation were the most important factors determining plant distribution. The effects of environmental factors, spatial factors and their interaction on the total variation of the U. lamellosa community pattern were quantitatively partitioned and showed that the contribution rates were 39.60%, 7.95%, 10.89% for environmental factors, spatial factors and their interaction, respectively, and 41.56% for other undetermined factors. Other unmeasured factors such as human activities and random events could play a role in determining the occurrence and distribution of herbaceous plants on the forest floor. Species coexistence was controlled by both niche differentiation and unified neutral theory of biodiversity.