It is necessary to study the seepage law of gas for building the underground natural gas storage in fractured rock salt so as to insure the natural gas storages to work safely,keep natural gas form seepage.This paper puts forward a coupled mathematical model for the seepage field of natural gas and the deformation field of rock and fractures,and establishes the numerical solution of finite element analysis,can provide some bases to determine the operation gas pressure of underground natural gas storage constructed in rock salt,also can provide the reference to evaluate the stability of underground natural gas storages.