Broad-leaved Korean pine forest is a typical zonal forest community in the eastern forest area of China, with high biodiversity. The temporal dynamics of the diversity of litter-layer beetles was investigated in broad-leaved Korean pine forest in Jiaohe, Jilin Province, and the responses of dominant groups were compared in different times, in order to provide scientific basis for the protection and utilization of litter-layer beetles in forests. Litter-layer beetles were collected by pitfall traps in adult beetles entire active period from mid May to late August during 2012 to 2013 at 4 sampling plots in the broad-leaved Korean pine forest. In total, 9849 specimens were collected, belonging to 22 families and 79 species, among which Carabidae, Silphidae, and Staphylinidae were the dominant groups. The species number, individual number and diversity index of litter-layer beetles were the highest in early July, and time had a significant impact on the number of individuals (P < 0.05). There was a low correlation among each index of litter-layer beetles, some species were more sensitive to environmental changes. The individual number of Carabidae in early July was significantly higher than during other times, and temporal dynamics of species number and individual number were not accordant. Additionally, the adaptability of Carabidae was higher than that of Silphidae and Staphylinidae in August. The individual number of Silphidae in early July was significantly higher than at other times (P < 0.01), and the temporal dynamics of species number and individual number were consistent. The adaptability of Silphidae was higher than that of Staphylinidae in July. The response of Silphidae to time change was the most sensitive, and their individual number could increase rapidly when the environmental conditions were appropriate. The variation of species and individual number of Staphylinidae was relatively small at different times, and the sensitivity of Staphylinidae to time change was the lowest. Because of the special life habits, the activity peak of predatism and saprophagous litter-layer beetles may be linked to the number of prey insects during every period.