Based on the HadISST sea ice concentration(SIC)data from 1961-2013,we define the Arctic sea ice seasonal melting index and analyze the spatial and temporal characteristics of Arctic sea ice seasonal melting extent.It turns out that in recent decades there are two significant decadal regime shift,late 1970sand the middle of 1990srespectively. Before the late 1970s,the oscillation of Arctic sea ice extent was decrease under the background of global warming,the seasonal melting extent(SME)was small but increased significantly;during the late 1970sand the middle of 1990s,the oscillation of the SME was maintain and had no significant trend;while after the middle of 1990s,although there is a hiatus of the global warming,the melting of Arctic sea ice is accelerating,especially after 2007,during which Arctic sea ice SME is greatly increased.Besides that,as the time goes by,the significant SME area expanded anticlockwise from the East Siberia sea to Beaufort Sea-north Canadian Arctic Archipelago gradual-ly,and expand to the central Arctic at the same time.Correspondingly,the total frequency of Chinese freezing rain(CFR)is decreasing during the past several decades and also has significant decadal regime shift.The inter-annual amplitude of the total frequency of CFR was large during 1962-1979,then turned small during 1980-1996,with close relation to SST instead of sea ice.After 1997the total frequency of CFR is at a low stage,but is increasing, which may mostly be influenced by Arctic sea ice variability.The key area of SST or SIC that influence CFR are different during different decadal epochs,resulting in certain atmospheric background circulation anomalies.There is a consistency between the change of CFR and the SME,which means that the decadal regime shift of the Arctic sea ice may be the cause of the decadal regime shift of Chinese freezing rain.