Abstract: The mole fraction of sulfur hexafluoride in the boundary layer of South Yellow Sea and East China Sea was observed based on discrete air samples collection and gas chromatography in spring of 2017.The mole fraction of sulfur hexafluoride ranged from 9.5×10^-12 to 14.0×10^-12, with an average value of(10.5±1.3)×10^-12, and showed an significant variation with distance away from land.Combined the underway wind data and back trajectory simulations, the high mole fraction of sulfur hexafluoride in the boundary layer of northeast and southwest areas of East China Sea may influenced directly by land-sea air mass transport from Japan, Korea and southeast part of China, respectively, where the human activities was intensive.However, the low mole fraction of sulfur hexafluoride in the other areas may influence more by air masses transport from the open shelf seas and Pacific Ocean, respectively.This study would be beneficial to the further studies of the spatial-temporal distribution of other atmospheric compounds and their regulate mechanisms in the China sea-shelf boundary layer.