Two hybrid rice strains,‘Ji 8945’（salt-tolerant） and‘Jinongda 808’（salt-sensitive）,were used in this experiment.Two-dimensional polyacrylamide gel electrophoresis and MALDI-TOF-MS/MS techniques were employed to isolate and characterize salt stress responsive proteins of hybrid rice seedlings in early period of 10-day old under normal and salt stress（100mM NaCl） conditions.The results showed that 21 or 35 up-regulated spots were significantly found in‘Ji 8945’and‘Jinongda 808’leaves compared with the control.Six of them were selected and identified by MALDI-TOF-MS/MS.Only two proteins were identified,i.e.,ribulose-1,5-bisphosphate carboxylase/oxygenase and enolase.