The permeability of rock salt is relatively small, and in the actual design and verification of the sealing of salt cavern UGS, rock salt is considered impermeable. However, due to the influence of disturbance loads especially when the rock mass undergoes volume expansion, the permeability can increase by 4~5 orders of magnitude. Meanwhile, the permeability of clayey interlayers is significantly greater than that of the pure rock salt, which leads to a higher risk of leakage. Also, during the gas injection and extraction, natural gas between adjacent salt caverns may flow along the interlayers in the pillars, especially when the pillars are narrow. To address the gas flow behaviors in bedded rock salt, an apparent permeability model considering Knudsen diffusion, pore surface diffusion, and pore heterogeneity was presented. The evolutions of gas permeability and gas flow behaviors with pressure were hinted by a gas seepage experiment carried out for model verification. A special focus was given to the seepage of gas in adjacent salt cavern pillars and salt cavern UGS with special geological conditions. This chapter could add further insights into the gas flow behaviors in the pore heterogeneous rock salt and be employed for tightness evaluation of salt cavern UGS and pillar width design of adjacent salt caverns.