In this study,three different strains of Dendrobium candidum seedlings were sprayed with different concentrations sodium selenite (Na₂SeO₃) solution on leaves and treated with low temperature stress under artificial temperature control growth conditions,then the effects of exogenous selenium on cold tolerance and recovery growth ability of D.candidum seedlings and their relationship with the relevant antioxidant physiological indexs were discussed.The result showed that:(1)Under low temperature stress,chlorophyll content,MDA content and proline content in the D.candidum seedlings with superior cold tolerance changed less than the strain with weaker cold tolerance.(2)Appropriate concentration of exogenous selenium(0.05~0.10 mg·L^-1) spraying treatment could alleviate the effect of chlorophyll degradation,also caused seedling antioxidant GSH-AsA activity significantly increase,meanwhile it increased the proline content and decreased the MDA content,improved the cold tolerance of D.candidum seedlings.However,the high concentration of exogenous selenium (＞0.20 mg·L^-1) treatment leaded to an opposite result.(3)After low temperature stress treatment,exogenous selenium (0.10 mg·L^-1) treatment could decrease the AsA content of seedlings significantly,but could promote the synthesis and accumulation of GSH,and effectively protected the comprehensive antioxidative capability of D.candidum ‘ZD-1’ seedlings in recovery growth period.