In deepwater drilling,the low temperature and high pressure favors hydrate formation in drilling fluid,which can bring great harm to deepwater drilling. A lot of work has been studied based on the developmet of gas hydrate formation and inhibition test device in deepwater drilling fluid.Research results shown that natural gas hydrate firstly formed in the gas-liquid interface;hydrate is more likely to form with the increase of stirring speed; sodium chloride can effectively inhibite the formation of gas hydrate in deepwater drilling fluid, polymeric alcohol and polyamine can delay the time of natural gas hydrate formation. Bentonite,PAC-LV,XC,SPNH has no obvious inhibition effect on the formation of gas hydrate.Gas components has important effect on natural gas hydrate formation, for alkanes, the larger the molecular weight, the easier for the gas hydrate to form.