Aiming at the limitations of conventional kinetic inhibitors，such as low tolerance to subcooling and short induction time in hydrate formations，a novel kinetic inhibitor P（NVP-g-NVCL-g-DMAEMA）was synthesized from N-vinylpyrrolidone（NVP）， N-vinylcaprolactam（NVCL）and dimethylaminoethyl methacrylate（DMAEMA）. The supercooling degree and induction time in the simulated gas hydrate inhibition processes were used as indexes to optimize the synthetic parameters. The product structure was characterized using infrared spectroscopy，while molecular dynamics simulation software extensively simulated the inhibition process and revealed the mechanism of hydrate kinetic inhibitors. The results showed that the optimum reaction condition was obtained as follows：8∶20∶1 mass ratio of NVP，NVCL and DMAEMA，0.5% initiator（1∶1 mass ratio of ammonium persulfate and sodium bisulfite）in total mass of monomer，65 ℃ reaction temperature and 6 h reaction time. When the mass fraction of inhibitor was 1.0%，the supercooling degree of hydrate formation increased from 2.6 ℃ to 9.6 ℃ under atmospheric pressure， meanwhile the induction time extended from 20 min to 945 min. The inhibition mechanism was mainly driven by inhibiting the formation of hydrate via hydrogen bond adsorption between the carbonyl groups on the five-membered ring or the seven-membered ring of molecular chain，as well as that on the ester group，and the water molecule. Nitrogen atoms on the molecular chain also formed hydrogen bonds and contributed to the adsorption. Furthermore，the steric hindrance of inhibitor also prevented the aggregation of hydrate molecules and thus inhibited the crystallization of hydrate. The kinetic inhibitor not only had active groups that could form hydrogen bonds to enhance the adsorption of inhibitor on hydrate cage，but also had alkyl chains that could affect the movement and distribution of methane molecules，further improving the supercooling degree and prolonging the induction time.