The Younger Dryas (YD) event which lasted from 12.9~11.6 ka BP is a rapid return to nearglacial conditions with a major impact on global climate that punctuated last glacial-Holocene transition period. The YD event was firstly found in records of midhigh latitude Northern Europe and North Atlantic vicinities and later identified broadly in North Pacific Oceans, Asia, North America, tropics and even in South Hemisphere. The mechanism of YD event is not clear although tremendous efforts have been paid over the past 30 years. Even the precise timing, duration and global impact remain ambiguous. The understanding of the magnitude of YD like event in temporal and spatial scales and its forcing mechanism may help us to forecast the possible environmental and ecological impacts in global scale due to anthropogenic forcing. This article reviewed the progress of studies on the YD event, including the most recent dating of the onset and geographic pattern of climatic impacts, and particularly the triggering mechanisms proposed in recent years. The disparities of precise dates among records for the YD onset may result from counting mistakes, regional environmental responses and rapid fluctuation of atmospheric ¹⁴C. Globally, the YD event was characterized by abrupt climate change with increasing anomalies in magnitude toward the poles and opposite signs between Hemispheres, which modulated by bipolar seesaw mechanism. It is generally accepted that the YD event is caused by a slowdown Atlantic Meridional Overturning Circulation (AMOC). However, the triggering mechanism of this slowdown is debatable. Besides the earliest hypothesis of Lake Agassiz outburst, alternative mechanisms such as meltwater discharge into Arctic Ocean, extraterrestrial impact or atmospheric circulation forcing have been proposed under various supportive evidences. Tropical process was suggested to play an additional role in abrupt climate change, of which high latitude was thought to be the modulator. The newest hypothesis suggested that YD event was an integral part of natural climate oscillation rather than a freak excursion. Finally, future directionstohave a complete understanding of the mechanisms of YD event are provided.