The invention relates to a method for predicting wellbore pressure and temperature field simulation as well as hydrate through deep-water test. The method comprises the following steps: preparing parameters; initializing a wellbore temperature field and pressure field; solving formation flow and bottom-hole pressure distribution information by using a seepage flow mathematical model for gas reservoir; inputting the formation flow and bottom-hole pressure distribution information into a wellbore flow model for iteration to solve a wellbore pressure profile and determine whether the wellbore pressure is converged or not; calculating thermophysical parameters, and calculating a total heat transfer coefficient of a formation section and a seawater section; substituting the wellbore pressure and the total heat transfer coefficient into a wellbore temperature field model to calculate the wellbore temperature profile of each node; determining whether the wellbore temperature profile is converged; determining whether tn is less than (tn+1) or not, if yes, outputting a well temperature-well depth curve and a hydrate generation temperature-well depth curve corresponding to the wellbore pressure, and determining whether a hydrate is generated according to the curves; or else, returning to predict the conditions of wellbore pressure and temperature field simulation as well as hydrate. According to the invention, the method can be widely used in the oil exploration process.