As a kind of well-performed and widely-used kinetic hydrate inhibitor(KHIs), polyvinylpyrrolidone(PVP) is attractive to many scholars in China and abroad. However, it is still controversial on the hydrate inhibition of PVPs with different molecular weights. In this paper, the formation of tetrahydrofuran(THF) hydrate was experimentally simulated under normal pressure and changing temperature to identify the effects of PVPs with different molecular weights at the same dosage on the formation and growth of TH...