Exogenous hydrogen sulfid (H2S) pretreatment promoted rice seedlings growth under Hg stress. H2S inhibited Hg transport from root to shoot. H2S increased bZIP60 and OsMT-1 expressions and NPT levels to sequester Hg in roots. H2S promoted seedlings growth even when the presences of Hg and SOD or CAT inhibitors. H2S attenuated Hg-induced oxidative damages in leaves by regulating O2·− and H2O2 productions.