In this paper,we present evolutions of the phase space density(PSD)spectra of ring current(RC)ions based on observations made by Van Allen Probe B during a geomagnetic storm on 23-24 August 2016.By analyzing PSD spectra ratios from the initial phase to the main phase of the storm,we find that during the main phase,RC ions with low magnetic moment μ values can penetrate deeper into the magnetosphere than can those with high μ values,and that the μ range of PSD enhancement meets the relationship: S(O+)>S(He+)>S(H+).Based on simultaneously observed ULF waves,theoretical calculation suggests that the radial transport of RC ions into the deep inner magnetosphere is caused by drift-bounce resonance interactions,and the efficiency of these resonance interactions satisfies the relationship: η(O+)> η(He+)> η(H+),leading to the differences in μ range of PSD enhancement for different RC ions.In the recovery phase,the observed decay rates for different RC ions meet the relationship: R(O+)> R(He+)> R(H+),in accordance with previous theoretical calculations,i.e.,the charge exchange lifetime of O+is shorter than those of H+and He+.