Gill Na -K -ATPase activities, serum concentrations of ions and hormones, specific growth rates and feed conversion efficiency in juvenile turbot (Scophthalmus maximus) (body weight of 7.16±0.07 g), which have been reared at salinities 12, 18, 24, 30 and 36 for 60 days, were investigated. The results showed that Na -K -ATPase activities and Na concentrations were 3.48-8.30 μmol ADP/mg protein/h and 169.99-180.00 mmol/L, respectively, the levels of which increased with the rise of water salinity, the highest ones all were observed at salinity 36, and lowest ones all at salinity 12. Na -K -ATPase activities and Na concentrations in the fish reared at salinity 12 was significantly lower than those in the control (P<0.05). K and Cl- concentrations were 2.37-3.47 mmol/L and 136.67-142.00 mmol/L, respectively, both of which had no significant differences between groups (P>0.05). Growth hormone and cortisol levels were 0.41-1.66 and 35.33-76.41 ng/ml, respectively. Growth hormone levels was the lowest in the fish reared at salinity 12, and the highest at salinity 36, both of which had significant differences in comparison with that of the control (P<0.05); while cortisol levels was the highest at salinity 12, and the lowest at 36, with no significant differences compared with that of the control (P>0.05). Specific growth rates and feed conversion efficiency were 1.45-2.00 %/day and 1.12-1.38%, respectively. Although both were the lowest at salinity 12, they were not significantly correlative with salinity. Thus, the results indicated that the changes in salinity could have significant impacts on Na -K -ATPase activities in gill, concentrations of Na ions, growth hormone and cortisol in serum of juvenile turbot. The results from this study provide important reference for salinity selection in turbot mariculture.