Abstract: Natural Gas Hydrate (NGH) will play an important role as a new energy source in the near future due to its great potential and advantages. There is a great amount of gas hydrate resource occurred in submarine sediments. The thickness of gas hydrate stability zone (GHSZ) could be used as a mean to predict the resource potential of NGH, and therefore, is critical for resource evaluation. This paper studied the factors which may affect the thickness of GHSZ. Our results show that water depth, geothermal gradient, salinity and gas composition may obviously affect the thickness of GHSZ in different ways. The thickness of GHSZ increases with the water depth, and exponentially decreases with geothermal gradient. The thickness decreases linearly while the pore water salinity increases. However, different kinds of salt affect the thickness of GHSZ with different functions. The composition of vent gas controls the thickness as well. C₂H₆, CO₂ and H₂S lead the increasing in thickness of GHSZ, whereas N₂ reduces the thickness of GHSZ, and the effect will be getting greater with the increase in content.