Dioscorea bulbifera virus-free plantlets were treated with different concentrations of NaCl to study the effects of salt stress on their growth and related physiological and biochemical indices.The results showed that the growth of Dioscorea bulbifera virus-free plantlets was markedly retarded under salt-stress.With the increasing of concentration,the total chlorophyll content and the activity of SOD decreased,while the contents of malonaldehyde (MAD) and proline increased.Moreover,under the salt-stress conditions,the content of proline in leaves of Dioscorea bulbifera virus-free plantlets had a significantly positive correlation to the content of MDA,but a significantly negative correlation to the total chlorophyll content and the activity of SOD.It was concluded that the changes of proline content in leaves could be used as a physiological index to reflect the hurt degree of Dioscorea bulbifera virus-free plantlets under salt-stress.