A laboratory experiment was conducted to assess the effects of the freezing thawingcycles (FTCs) on soil microbial biomass carbon (MBC), and CO₂ and CH₄ emissions from wetland soils in the continuous permafrost zone (TQ) and seasonally frozen region (JC) of Northeast China. Soil samples were incubated at different frost intensities \[+5 (control), -5, and -15 ℃\] for 12 h respectively, and then thawed at +5 ℃ for 12 h. These freezethaw cycles were repeated for 0, 1, 5, 10, and 15 times. The results showed that the CO₂ and CH₄ emission rates and MBC of two  types of soil decreased after the first freezethaw incubation, and presented an increase and then decrease pattern and then trended to be stable with the increases of cycling times. Compared with the control (5 ℃) and low frost intensity (-5 ℃) treatments, high frost intensity (-15 ℃) significantly promoted CO₂ and CH₄ emissions but did not significantly influence MBC. At -15 ℃, the cumulative CO₂ emissions from TQ soil reached 679.99 mg·kg^-1 after 15 FTCs, which was about 50% higher than that of JC soil (454.32 mg·kg^-1). The highest cumulative CH₄ emission from TQ soil was 334.49 μg·kg^-1 at -5 ℃ after 15 FTCs, while this value was 600.07 μg·kg^-1 at -15 ℃ for JC soil. The temperature sensitivities of methanogens might bedifferent between these two frozen soils during the freezingthawing cycles. Our results provide scientific data for the assessment of global climate change on soil carbon turnover in the mainpermafrost regions of Northeast China.