Gas hydrates are solid compounds similar to ice crystals where cages of water molecules enclose molecules of natural gas mostly being methane a well as ethane, propane, etc. It has long been known that the natural gas hydrates occur globally in sediments mainly in the continental slope and in permafrost regions of the continent. Over the past years, geoscientists had acquired a lot of information about the physical and chemical characteristics, geological conditions of formation and concentration, distribution of the gas hydrate, the technology and methold of explorating and exploitating, as well as the potentially influence on environment. Scientific ocean drilling provided the only avenue for us to gain sample of gas-hydrate and bearing-gas-hydrate sediments and free gas from deep setting, especially Leg164 and Leg204 of Ocean Drilling Program (ODP). By studying the data from ODP, geoscientists had analyzed in situ property of bearing-gas-hydrate sediments, discussed reacting mechanism among gas, water, sediment and gas-hydrate. The Integrated Ocean Drilling Program (IODP) will provide a new opportunity for us to research the Earth's history and the System's Processing (ESP), and will reveal the importance of gas-hydrate in the process.