Abstract: Structures of hydrate haveⅠ, Ⅱ and H structure. At present, the theoretical models are based on Van der Walls model. Gas Hydrate Formation Conditions prediction models have two empirical or semi-empirical correlation models and 6 thermodynamics phase equilibrium models. The 8 models are adopted to calculate gas hydrate formation temperatures on given pressures condition. All calculating temperature values are lower than field data. Calculating errors are little with field data while pressures are below 5 MPa. But calculating errors are great with field data while pressures are above 5 MPa. 6 thermodynamics phase equilibrium models calculating errors are in turn : VDW > PP > HJ > NR > Duo & . Guo88 > Chen & Guo96, namely Duo & Guo88 and Chen & Guo96 are best calculating models for gas hydrate formation conditions prediction.