In order to restore the vegetation of forests, China has implemented the project of restoring the farmland to the forest. With the advancement of this project, the artificial vegetation restoration area adjacent to the forest is expanding. In this study, a secondary oak forest, its adjacent restored poplar forest and the secondary oak forest-restored forest ecotone were selected as the study sample plots, and the ground-dwelling beetle community was investigated by pitfall trap method for exploring the diversity characteristics of the ground-dwelling beetle community in this complex ecosystem, in order to reveal the relationship between the ground-dwelling beetle and the environmental changes. In this study, 2458 ground-dwelling beetles belonging to 94 species of 24 families were collected from the secondary oak forest and its adjacent restored poplar forest from April to September 2017, of which Scarabaeidae, Carabidae and Silphidae were the dominant communities of ground-dwelling beetles in the sample plots. The order of the species number and individuals number of ground-dwelling beetles in the different types of vegetation was the secondary oak forest > ecotone > restored poplar forest in turn, with significant differences. The estimation of nonparametric species richness showed that the sampling intensity was not fully saturated, indicating that more surface beetle species could be collected. The Margalef richness index, Simpson diversity index (λ), Hill diversity index (N₂), Pielou evenness index (E₁), Hill evenness index (E₂) and modified Hill evenness index (E_Hill) of surface beetles were significantly different in the different habitats, and higher diversity and evenness of the surface beetles were maintained in the restored poplar forest, indicating that the restoration and re-naturalization of forest vegetation could increase the insect species and community stability. The community similarity analysis indicated that the ground-dwelling beetle community among the secondary oak forest, the ecotone and the restored poplar forest was at the middle level of dissimilarity. The edge effect intensity analysis suggested that there was a negative edge effect in the ecotone between the secondary oak forest and the restored poplar forest.