Preparation technology of Zn- peptide complexes was studied and its effects on growth performance and serum biochemical indicators were investigated by feeding Oreochromis Niloticus with feedstuff containing Zn-peptide complexes. The optimal conditions of synthesis reaction for Zn-peptide complexes prepared by zinc with peptide were described in the following: pH 5.0, temperature 80°C, and mass ratio of peptide-Zn 4:1, reaction time 30 min. Under such conditions, yield of Zn-peptide complexes was up to 54%, chelating rate of Zn was 55%, and Zn content of the complex was 6.5×104 mg/kg. A new complex formed from Zinc with peptide was identified by spectrum analysis. The 49-day feeding experiment showed that the complexes remarkably increased specific growth rate, survival rate, content of lysozyme and activity of superoxide dismutase (SOD) and alkaline phosphatase (AKP). Feed conversion ratio was significantly reduced as the additive increased. The content of total protein, albumin, and globulin were elevated too. And growth performance, body immunity, anti-oxidation function of Oreochromis Niloticus was significantly increased while the amount of the additive was 2.4 ~ 4.8 g/kg feedstuff in the experiment.