To ensure the stability of the construction and operation of subway lines in a soft stratum， the soil strength around the structure can be improved by grouting reinforcement. However， according to different reinforcement degrees， the discontinuity of the soil medium will be gradually changed， and the corresponding dynamic transmission characteristics will be changed， so the dynamic response distribution mode of the reinforced area and the surrounding stratum under the driving condition needs to be further explored. A dynamic coupling model of subway line-stratum with reinforcement area is established based on the analytical theory. The reinforced soil and the natural soil are considered as saturated porous media with different physical and mechanical properties， and the corresponding dynamic equations are derived respectively by Biot theory. The subway structure is regarded as an infinite cylindrical shell with uniform thickness， which is described by the theory of the thin-walled cylindrical shell under the torsion-free condition. According to the displacement and stress continuity conditions between interfaces of the dynamic system， the vibration equations of the above parts are combined into a set of coupled dynamic equations， and the vibration of the subway peripheral stratum containing the reinforced area is calculated， the effects of stiffness and viscous damping of the reinforcement area on the distribution and transmission of the stratum dynamic response are further compared. The results show that under the steady state action， the maximum tangential acceleration of the stratum around the subway shows a cicada-wing distribution at 30° on both sides of the structure diagonally downwards， and the maximum radial acceleration occurs in the soil in the direction of the load. Due to the harmonic characteristics of the input waveform， the acceleration decays fluctuating in the stratum， but an obvious amplification of tangential acceleration occurs in the reinforcement area. After the vibration enters the natural soil， the dynamic response is significantly attenuated by the effect of stratum damping. Increasing the stiffness of the reinforcement area is conducive to reducing the conduction of tangential acceleration， while the radial acceleration changes little， and the transmitted dynamic response increases when the viscous damping decreases.