Bubble curtain could be used as one of the fish controlling techniques in sea ranching. In the present study, the behavioral responses of rockfish (Sebastes schlegeli) were observed by changing the location of the bubble curtain in the water tank and the density of the fish, and the deterrent effectiveness of the bubble curtain on  rockfish of different densities was studied using the methods of observation, controlled trials and variable-controlling. Results show that: 1) when there were 20 fish in the tank, the bubble curtain was set at the 1/4, 1/2 and 3/4 of the rectangular tank lengthwise, and the blocking rates were 98.2%, 88.4% and 92.9%, respectively; 2) when the bubble curtain was set at 1/2 of the tank lengthwise, and the experimental fish were of 5, 10, 15 and 20 in number, respectively, the blocking rates correspondingly reached 100%, 85.7%, 100% and 88.4%, and the deterrent effect was good（in which the densities of the rockfish were 1.56, 3.12, 4.69 and 6.26 individuals per square meter respectively); 3) no significant relationship between the fish density and the blocking effectiveness was observed due to the high blocking rates. The results provided a reference to the fish controlling technique in sea ranching and the fish blocking technology used in water intake areas.