Abstract: An experiment was conducted with cucumbers（Cucumis sativus） of ’Gai Liang Jin Chun No 2’ growing in a nutrient solution culture system and effects of extraneous nitric oxide on growth and active oxygen metabolism were analyzed and studied.Results show that addition of 100 μmol·L^-1 extraneous sodium nitroprusside（SNP）,a nitric oxide donor,significantly alleviated the injury that NaCl stress brought to the plants,increased obviously plant growth,and activity of SOD,POD,CAT and APX,and accelerated accumulation of proline（Pro） in the roots.Meanwhile,extraneous nitric oxide markedly decreased membrane permeability,O^-·₂ producing rate,MDA and H₂O₂ content of the roots.