This study evaluated the salt tolerance of Italian ryegrass varieties under various salt stress conditions. Seven varieties, including Kowineary, Greencall, Greenfarm, Greenfarm 3, IR 603, IR 605, and IR 901, were used in this experiment. Under various salt concentrations, there was no significant decrease compared to the control at salt concentrations of 0.1% to 0.3%. IR 901, Kowineary, and IR 605 had a lower relative reduction rate, but the absolute growth of IR 603 was the highest among the varieties. Among chlorophyll fluorescence parameters, ABS/RC, TRo/RC, ETo/RC, and DIo/RC values (activities expressed per reaction center) showed a significantly negative correlation with growth rates. In the experiment where the salt concentration was drastically increased, the growth decreases in Greenfarm 3 and IR 901 were relatively small compared to other varieties. Among the relative ratio of chlorophyll fluorescence parameters, ABS/RC, TRo/RC, ETo/RC (after 1 hour of salt concentration increase), and PIABS (3 hours, 7 days) showed a significant positive correlation, and DIo/RC (3 hours, 1 day) showed a negative correlation with plant growth. In the experiment where the salt concentration was drastically decreased, the growth increases in Greenfarm, IR 901, and Kowineary were relatively high compared to other varieties. Among the relative ratio of chlorophyll fluorescence parameters, ABS/RC, ETo/RC, DIo/RC (5 hours), and PIABS (1 hour) showed a significant positive correlation with plant growth. In summary, among the seven varieties, Kowineary and IR 901 had superior relative growth (compared to the control) under various salt stress conditions. IR 603 showed a greater decrease in relative growth but had the highest absolute growth amount under salt stress conditions. In addition, some parameters related to chlorophyll fluorescence showed a significant correlation with early growth, which could be used as indicators of the initial growth of IRG under salt stress.