The purpose of this paper was to investigate the effects of seaweed powder and antibacterial peptide and their synergy on performance and egg quality of laying hens. A 4×2 (seaweed powder × antibacterial peptide) completely random experiment design was used. A total of 480 Hyline brown laying hens were randomly divided into 8 groups with 5 replicates per group and 12 hens per replicate. Seaweed powder supplemental levels were 0, 1.0%, 3.0% and 5.0%, respectively, and antibacterial peptide supplemental levels were 300 and 600 mg/kg, respectively. The pre-trial period lasted for 7 days and the trial period lasted for 28 days. The results showed as follows: 1) dietary supplemented with seaweed powder significantly increased laying rate, the ratio of feed to egg, yolk color and eggshell strength (P<0.05). 2) Dietary supplemented with antibacterial peptide significantly increased laying rate and eggshell strength (P<0.05). 3) The synergy between seaweed powder and antibacterial peptide significantly increased laying rate, the ratio of feed to egg, yolk color and eggshell strength (P<0.05). It is concluded that seaweed powder and antibacterial peptide have synergistic effects on performance and egg quality of laying hens. The suitable levels are 5% seaweed powder and 300 mg/kg antibacterial peptide in the whole period.