Abstract: Gas hydrate is usually formed during the transportation and treatment of oil and gas, resulting in the plug of gas pipeline and equipment. To solve this problem, three thermodynamics calculation formulas are analyzed. Using the fall of inhibitors freezing point ΔT to calculate formation temperature of natural gas hydrates is considered to be better. It is not limited by kinds and concentration of inhibitors and the fall of freezing point could be measured easily. The result of testing methanol and mono-ethylene glycol in a pipeline show that adding 10% inhibitors to the pipeline can prevent hydrates formation. Kinetic inhibitors are top research at present. They are separated into two kinds (polymer and surface active agents). Their characteristics, mechanisms and application prospect are introduced separately. Polymer inhibitors have better efficiency. The field application of VC-713 is given. In practice, combining thermodynamics inhibitors with kinetic inhibitors can be better.