Construction of ultra-deep salt cavern gas storage is a difficult problem for many years. For the benefit of this problem, selecting Ningjin Salt Cave Gas Storage, the mechanical properties were studied by uniaxial compression tests and triaxial compression tests, and the stability analysis model of salt chamber was established by FLAC3D so as to provide reference for drilling and completion technology, cavity construction technology, injection and production technology of salt cavern gas storage in Ningjin. by researching: (1) According uniaxial compression tests, salt rock possesses certain brittleness, mudstone and fine sandstone show obvious brittleness. The deformation capacity of salt rock is better than that of mudstone and fine sandstone under the same stress state. The average of elastic modulus of salt rock is 4.79 GPa, the average of poisson's ratio is 0.07, The average of compressive strength is 22.01 MPa. (2) According to the test of triaxial compression, salt rock show more obvious characteristics of ductile rock than mudstone and fine sandstone when the confining pressure is greater than 5MPa. The main form of destruction is bulging, the behavior of strain-hardening increase with the confining pressure, no obvious fracture surface, salt rock has strong plastic deformation characteristics. (3) The expansion area and displacement of cavity wall decrease gradually with the increase of internal pressure,internal pressure of Ningjin salt cavern gas storage is not less than 20 MPa.