Abstract: The effects of different temperature， salinity and body weight on respiration and excretion of juvenile Sciaenops ocellatus were studied， and the results showed that: temperature， salinity and body weight had significant effects on oxygen consumption rate and ammonia excretion rate （P<005）. The oxygen consumption rate increased with temperature and there was an exponential correlation between them. The ammonia excretion rate and oxygen\|nitrogen ratio increased significantly with temperature and the ammonia excretion rate was a power function relation with temperature from 10 ℃ to 30 ℃. The Q10 breathing was in normal level， while the level of excretion Q10 was low; From S 10 to S 40， the oxygen consumption rate and oxygen\|nitrogen ratio decreased first then increased and finally decreased， and the ammonia excretion rate decreased first and then increased; The oxygen consumption rate and ammonia excretion rate of juvenile Sciaenops ocellatus was decreased with increasing body weight and power function related， but the effect of body weight on oxygen\|nitrogen ratio was not significant.

Key words: juvenile Sciaenops ocellatus, temperature, salinity, body weight, respiration, excretion