Picophytoplankton are responsible for much of the carbon fixation process in the Arctic Ocean,and they play an important role in active microbial food webs.The climate of the Arctic Ocean has changed in recent years,and picophytoplankton,as the most vulnerable part of the high-latitude pelagic ecosystem,have been the focus of an increasing number of scientific studies.This paper reviews and summarizes research on the characteristics of picophytoplankton in the Arctic Ocean,including their abundance,biomass,spatial distribution,seasonal variation,community structure,and factors influencing their growth.The impact of climate change on the Arctic Ocean picophytoplankton community is discussed,and future research directions are considered.