Since the industrial revolution,the content of anthropogenic greenhouse gas is increasing.As a result,the global surface air temperature grows rapidly.However,the global surface air temperature has stalled since 1998,despite the greenhouse gas steadily increases.This paper reviewed the latest research progress on this phenomenon,especially the mechanism of the global warming hiatus.There are two main viewpoints on the mechanism,namely,the external forcing and natural variability.The former includes the influence of solar activity,volcanic aerosol particles,man-made aerosol particles and stratospheric water vapor forcing.Scientists in the opinion of natural variability hold the idea that the missing heat produced by human activity has entered the deep ocean,especially the layer below 700 m.They believe that the oceans play a key role in the global warming hiatus.There are two main ideas for that:Pacific Decadal Oscillation(PDO),especially the cooling in the eastern tropical Pacific,and the Atlantic Meridional Overturning Circulation(AMOC).The widely accepted idea on the mechanism of recent global warming hiatus is natural variability.The missing heat has entered the deep ocean.But it still remains controversial which ocean basins gain the missing heat.