Abstract: Sound Speed Profile(SSP)is the main factor to reallocate acoustic energy.Reverberation consists of two-way transmission and backscattering.Simulations and theoretical analysis had been made based on the full-wave reverberation theory,which began with the effect of SSP on the vertical structure of normal modes,to illustrate effect of SSP on the vertical structure of two-way transmission loss,as well as the vertical structure of backscattering intensity in shallow water.On this basis the Vertical Structure of Reverberation Average Intensity(VSRAI)had been analyzed.The result shows that VSRAI can be recognized as steady with SSP if the transmission range is not large enough.While the vertical stricture will have significant change when the transmission range is large enough with the relative sound speed gradient in order of 10^-4 m^-1.An experiment in shallow-water waveguide with downward refracting profile showed good agreement with above conclusion,which VSRAI kept steady in limited reverberation during.