Abstract: For gas injection process of gas storage sealed by faults, fluid mechanics, seepage mechanics and gas reservoir engineering methods are used to drive the pressure distribution equations for three stages, i.e. from the wellhead to the bottom, from the bottom to the near wellbore zones, and from the near wellbore zones to the fault, of the injection-production well, and to prepare the forecast charts under different flow and geological parameters. These equations and charts provide theoretical basis and reference for tracking and evaluating the pressure in the whole process from wellhead to fault in the gas injection process. Using the equations, pressure at gas storage fault can be calculated according to the gas injection wellhead or bottomhole pressure to determine whether the fault pressure exceeds the upper limit of design pressure, or reasonable injection pressure limits of gas injection wells can be calculated and the feasibility to improve the capacity of gas storage is evaluated according to the maximum opening pressure at the fault.