As a natural phenomenon, soil freeze-thaw processes often occur in the regions of mid- and high latitudes and high altitude. Freeze-thaw can alter the soil physicochemical and biological properties, which thereby results in changes in soil nitrogen transformation and N₂O production and hence emission. Up to now, the impacts of freeze-thaw processes on soil nitrogen transformation found in previous studies remain inconsistent and large discrepancies have been found in the data on the contributions of N₂O losses during freeze-thaw period to annual emissions. In addition, this review also addresses the effects of freezing or a freeze-thaw cycle on major soil nitrogen transformation processes, including mineralization, immobilization, nitrification and denitrification, and possible explanations are discussed. Meanwhile, four potential mechanisms relating to N₂O emission intensity during the freeze-thaw period, such as N₂O trapped in and below the frozen layer and released from thawed soil, N₂O induced by circumstance and substrates, N₂O inhibited by N₂O reductase and N₂O enhanced by chemodenitrification, are systematically analyzed. The implications of global warming for soil freeze-thaw patterns are addressed, as well as the need to investigate alteration of soil nitrogen transformation and N₂O emission as affected by these circumstances. At last, some theoretical problems and perspectives of the study are brought forward.