Abstract: A 43-day growth experiment was conducted in a recirculated filtered rearing system to identify the optimum dietary protein level for juveniles of the southern catfish, Silurus meridionalis, at the water temperature of 27.5±0.2℃. White fishmeal was used as the main dietary protein source to formulate isocaloric experimental diets at six protein levels (39.9%,43.7%,46,8%,51.6%,55.7% and 59.1%). The results showed that dietary protein levels influenced significantly the specific growth rate (SGR), feed conversion efficiency (FCE) and protein efficiency ratio (PER) (P0.05), but the ration level of energy (RLe). was not affected Negative correlation was observed between ration level of dry matter (RLdm) and dietary protein level (r=-0.62 , P0.01). However . The ration level of protein (RLp) was positively related to dietary protein level (r=0.96, P0.01). It is suggested that the optimum dietary protein level for the catfish should be 47-51%.