Abstract: In midhigh northern latitude and high altitude regions, a phenomenon of soil freezingthawing cycles generally occurs in the late autumn and early spring. With the global warming, effects of such freezingthawing cycles on the processes of soil carbon (C) and nitrogen (N) cycling are attracting more attention. In the present study, we collected soil samples from different types of forest in Changbai Mountain, including Pinus koraiensis, Betula platyphylla and Larix olgensis. We carried out a laboratory incubation experiment to investigate how freezingthawing cycles (-10 to 10 ℃) affect soil C and N mineralization at low soil water content (40%) and high water content (supersaturation). The results show that freezingthawing cycles significantly restricted C mineralization rate under different water conditions (except for the P. koraiensis soil at low soil water content). Such restriction was more pronounced with increase in the frequency of freezingthawing cycles. Freezingthawing cycles interacted with soil water content to affect soil N mineralization; they increased N mineralization rate at the low water content, whereas such influence was different at the high soil water content. These results indicate that freezingthawing cycles in the late autumn and early spring significantly drove soil C and N mineralization in Changbai Mountain, the extent of which depended on freezingthawing frequency and soil water content.