The relationship between spring sea surface temperature in the North Atlantic and extreme cold event (ECE) frequency in eastern China at interannual timescale is investigated in this paper. The results show that the North Atlantic tripolar SST mode (NATSST) can significantly affect the first leading mode of ECE frequency in eastern China after the late 1980s, but not before. Further mechanistic analysis suggests that such an interdecadal change in the relationship between the two could be related to the difference in the NATSST-excited wave trains before and after the late 1980s. In 1960-1987, the NATSST-related wave train propagates from the North Atlantic to southern Central Asia, which is located more southward and consequently has a weak influence on atmospheric circulations and ECE in eastern China. However, in 1992-2019, NATSST can excite two wave trains. The northern one is associated with the North Atlantic Oscillation (NAO), which propagates eastward from the North Atlantic to mid-high latitudes of Eurasia, resulting in anomalous cyclonic/anticyclonic circulation in the Mongolian region. The southern one propagates eastward from the North Atlantic to mid-low latitudes of Eurasia, leading to anomalous cyclonic/anticyclonic circulation in southern-central China. These cyclonic/anticyclonic circulations are favorable/unfavorable to the southward movement of cold air from middle and high latitudes, and also change the surface heat flux in eastern China, consequently providing favorable/unfavorable climate background conditions for the occurrence of ECE. Through these physical processes, NATSST can significantly influence the interannual variability of the frequency of spring ECE in eastern China after the late 1980s, but not before.