With the advent of climate change, winter temperatures have been steadily increasing in the middle-to-high latitudes of the world. However, we have not found a corresponding decrease in the number of extremely cold winters. This paper, based on Climatic Research Unit (CRU) re-analysis data, and methods of trend analysis, mutation analysis, correlation analysis, reports on the effects of Arctic warming on winter temperatures in Heilongjiang Province, Northeast China. The results show that: (1) during the period 1961- 2018, winter temperatures in the Arctic increased considerably, that is, 3.5 times those of the Equator, which has led to an increasing temperature gradient between the Arctic and the Equator. An abrupt change in winter temperatures in the Arctic was observed in 2000. (2) Due to the global warming, an extremely significant warming occurred in Heilongjiang in winter, in particular, after the Arctic mutation in 2000, although there were two warm winters, more cold winters were observed and the interannual variability of winter temperature also increased. (3) Affected by the warming trend in the Arctic, the Siberian High has intensified, and both the Arctic Vortex and the Eurasian Zonal Circulation Index has weakened. This explains the decrease in winter temperatures in Heilongjiang, and why cold winters still dominate. Moreover, the increase in temperature difference between the Arctic and the Equator is another reason for the decrease in winter temperatures in Heilongjiang.