This study was investigated to monitor the effects of thinning on ground beetle assemblages in Pinus rigida plantations in the Byeonsanbando National Park. The 30% and 50% thinning was performed at August in 2014, and ground beetles were sampled using pitfall traps from 2015 to 2017. We also investigated ground beetles in Pinus rigida plantations without thinning and natural broadleaved-deciduous forests. A total of 2,635 individuals were caught and identified to 20 species. Among 20 species, Synuchus cycloderus (1,045 individuals) and Chlaenius naeviger (356 individuals) were dominant. One of edge-preferring species, C. naeviger, was more abundant in the study plot with thinning compared to others. Bray-Curtis dissimilarity was decreased between study years, i.e. species composition of ground beetles seems did not affected by thinning. However, the dissimilarity was increased between study treatments when the most dominant species was excluded from the analysis. However, the results of this study should be interpreted carefully, because spatial distance between treatments was rather short, and study area was too small to understand the effect of thinning.