This study was to overexpress the AtNHXS1,a new vacuolar Na+/H+ antiporter gene obtained from AtNHX1 by DNA shuffling and study its effect on the salt tolerance of rice (Oryza sativa L.).AtNHXS1 was transformed into Oryza sativa L.ssp.japonica cv.zhonghua11 by Agrobacterium-mediated method and confirmed by polymerase chain reaction (PCR) and Southern blot.The transcription level was analyzed by RT-PCR.The contents of Na+,K+ and the ability of salt tolerance were compared between transgenic lines and wild-type lines.Twenty T2 transgenic lines haboring AtNHXS1 were obtained,two of which were verified as insertion of single gene by Southern blot.RT-PCR analyses showed that the expression levels of AtNHXS1 mRNA were significantly higher after salt treatment in transgenic lines.After salt stress,it was found that the growth status,dry weight,fresh weight and Na+ content of transgenic rice plants were significantly higher than those of wild-type plants,however the accumulation of K+ was slightly low.Transgenic plants were able to survive and recover after exposure to 300 mmol/L NaCl for 5 days,whereas wild-type plants could not.These results demonstrated that overexpression of AtNHXS1 significantly improved the salt tolerance of rice.