Thirty-eight rice varieties identified to be tolerant to salt stress previously were identified repeatedly with the 9-level identification methods of International Rice Research Institute using 0.8% instead of 0.5% NaCl solution in order to obtain extremely salt-tolerant rice varieties. Meanwhile, the effects of salt concentration on sprout rates of these varieties were studied. The results showed that high-concentration salt solution restrained significantly sprout rates of these varieties. six rice varieties were identified to be extremely resistant to salt, of which, one variety ranked first-level tolerance, four varieties second-level tolerance and one variety third-level tolerance. Increase of seedling height were limited by high-concentration salt solution, but difference between varieties extremely resistant to salt was not significant. The effects of salt solution on growth rate of rice leaves were different depending on varieties extremely resistant to salt.