With the development of oil and gas drilling from shallow water area to the deep water area, more and more attention has been paid to inhibition on natural gas hydrate in deep water drilling. As a perfect hydrate kinetic inhibitor, polyvinylpyrrolidone (PVP) was widely used in oil and gas production and transportation. Drilling fluids with different PVP concentrations were used in a shallow water gas field. Firstly, the low temperature normal performance was evaluated. Then the inhibition of PVP in the drilling fluid was investigated at 4oC and 6 ~ 10 MPa in a 1.2-liter reactor through temperature and pressure change during reaction. The experimental results show that 2.0wt% of PVP can affect the rheological properties which will not meet the requirements of drilling. The PVP of 0.5wt% and 1.0wt% have inhibiting effect in the drilling fluid, the higher concentration the more obvious suppression. However, the addition of the PVP cannot completely inhibit the formation of hydrate.