The effect of nitric oxide (NO) on growth of maize seedlings under 100 mmol/L NaCl stress was studied. The results showed that 0.1-200 mumol/L sodium nitroprusside (SNP), especially 100 mumol/L SNP, increased dry accumulation in maize seedlings significantly, the chlorophyll content, K(+)/Na(+) ratio and (Spd+Spm)/Put ratio, and decreased electrolyte leakage. These results suggest that NO may alleviate the damage caused by NaCl stress through increasing K(+) uptake and transport to shoots and decreasing Na(+) uptake and transport, and also through enhancing the conversing of Put to Spd and Spm.