Abstract: The effects of exogenous H2S on physiological and biochemical characteristics of cucumber hypocotyls and radicles under cadmium stress were studied. The results showed that the inhibited growth of cucumber hypocotyls and radicles by cadmium was alleviated by different concentrations（300 μmol · L-1，600 μmol · L-1，900 μmol · L-1，1 200 μmol · L-1）of NaHS treatment，especially under the 900 μmol·L-1 treatment. NaHS treatment significantly increased activities of amylase，SOD，POD，CAT and APX as well as the capacity of α，α-diphenyl-β-picrylhydrazyl radical（DPPH· ）and hydroxyl radical（OH· ）scavenging in both hypocotyls and radicles of cucumber，as the results，the accumulations of MDA and H2O2 were decreased. Otherwise，the treatments with other sodium salt including Na2S，Na2SO4，NaHSO4，Na2SO3，NaHSO3 and NaAc had no significant effects on the growth of cucumber hypocotyls and radicles. Based on these results，it could be concluded that the function of NaHS was attributed to H2S from it.

Key words: cucumber, hypocotyl, radicle, hydrogen sulfide, cadmium, antioxidant enzyme