This study seeks to identify the community structure and diversity of ground-dwelling beetles in natural forests and adjacent restored farmland, examine the presence and intensity of the edge effect in the ecotone, and assess the contribution of plantation forests to the protection of biological diversity. The results will provide guidance for forest management that aligns closely with nature. From April to September in 2017 and 2018, the research was focused on the boundary between the natural broad-leaved mixed forest and the young Pinus koraiensis plantation forest, extending 120 meters on both sides, with sampling points established every 30 meters. The ecotone is marked by the central sampling point and another 30 meters away, with three transects in total where ground-dwelling beetles were continuously captured using the pitfall trapping method. A total of 6,990 ground-dwelling beetles were collected, representing 30 families, 124 genera, and 178 species. The species counts were 113 in the broad-leaved mixed forest, 125 in the ecotone, and 134 in the P. koraiensis plantation forest, with 79 species shared across all three habitats. Hill diversity indexes indicated that the number of species, common species, and dominant species in the three habitats were ranked as follows: P. koraiensis plantation forest > ecotone > broad-leaved mixed forest. Significant differences were observed in both the number of individuals and species of Carabidae and Cetoniidae across the habitats (P ＜ 0.05), as well as in the number of individuals of Silphidae (P ＜ 0.05). There were notable variations in the number of individuals and species of dominant families within the same habitat (P ＜ 0.05). The individual counts of Aclypea daurica, Carabus canaliculatus, Onthophagus ater, Ampedus sanguinolentus, and Synuchus orbicollis significantly differed across habitats (P ＜ 0.05). The Margalef and Shannon indexes indicated that the P. koraiensis plantation forests have significantly higher diversity than the broad-leaved mixed forests (P ＜ 0.05). The results from PERMANOVA and NMDS showed significant differences in community structure across the three habitats (P ＜ 0.05), and SIMPER analysis reveals the highest mean dissimilarity between the broad-leaved mixed forest and the P. koraiensis plantation forest, followed by the dissimilarity between the P. koraiensis plantation forest and the ecotone, and the lowest between the broad-leaved mixed forest and the ecotone. Species contributing more than 0.01 accounted for 48.18%, 43.16%, and 39.64% of the heterogeneity in each respective habitat. The Jaccard similarity coefficient indicated moderate similarity in species composition of ground-dwelling beetles across the three habitats. The edge effect index revealed a slight positive effect among the ground-dwelling beetles in the study area. The community structure demonstrated heterogeneity in the ecotone between the natural broad-leaved mixed forest and the P. koraiensis plantation forest. The diversity of ground-dwelling beetles in the P. koraiensis plantation forest was similar to that in the broad-leaved mixed forest, suggesting a beneficial ecological impact on the plantation. However, the differences in community composition indicated that the P. koraiensis plantation forest cannot substitute the broad-leaved mixed forest.