This experiment was conducted to assess the effects of dietary protein (44%,48% and 52%) and antibacterial peptide (0.01% and 0.02%) on growth performance, serum biochemistry, digestive enzyme and antioxidant abilities of grouper (Epinephelus akaara). The experimental diets were named as:D1 (44%, 0.01%), D2 (48%, 0.01%), D3 (52%, 0.01%), D4 (44%, 0.02%), D5 (48%, 0.02%) and D6 (52%, 0.02%). Each diet was fed to 3 replicates and the experiment lasted for 8 weeks. The results show as follows:In certain range, Weight gain (WG), specific growth rate (SGR) and feed conversion ratio increased with protein level and ABP concentration increasing, and D5 was significantly higher than D1 (P<0.05). The morphological indexes, Hepatosomatic index (HSI), Viscerosomatic index (VSI) and Intraperitoneal fat index (IPF) of D6 were significantly lower than D5 (P<0.05). Crude fat content of fish fed diet D4 was significantly lower than D1 (P<0.05). Serum total protein (TP) and albumin (ALB) increased with protein and ABP increasing (P<0.05), glutamic-pyruvic transaminase (ALT), glutamic oxalacetic transaminase (AST) and glucose (GLU) were lower in D3 and D5 (P<0.05). Trypsase of D5 was higher than other groups (P<0.05), and Peroxidase (POD) of D1 was significantly lower than other groups (P<0.05). ABP could increase Pepsin, Catalase (CAT), POD and decrease Malondialdehyde (MDA) content (P>0.05). The result shows 0.02% ABP supplementation at 48% protein level can improve growth, increase digestive enzyme activities and antioxidant abilities, and decrease FCR.