This paper studied the effect of Na2S2O3 on accumulation of mercury (Hg) by two common plant species selected, Chlorophytum comosum and Setcreasea purpurea, in medium containing 10μgL−1 HgCl2. We compared the Hg accumulation in roots, stems and leaves of two plant species in medium with and without Na2S2O3. The purpose of this study was to assess the effect of Na2S2O3 on Hg uptake and translocation by C. comosum and S. purpurea. The amount of Hg uptaken by two plant species was determined using cold vapor atomic absorption spectrometry. The results demonstrated that Na2S2O3 inhibited the enrichment ability of two plant species selected to some extent.