Abstract: The barley was used as experimental material, and the metal ions (K+, Mg2+, Zn2+, Ca2+ and Cu2+) with different concentrations (0, 20, 40, 60, 80 and 100 mg/kg) were respectively added in the steeping phase of barley. The related indexes of the resulting product malts, including the activities of the oxidoreductases SOD, CAT, POD and PPO, total phenol content, DPPH scavenging capacity, reducing power and TBA value, were determined. The objective of the above conduction was to investigate the effect of metal ions on malt endogenous oxidoreductases and antioxidant activity in vitro. The results show that the effect of each metal ion of different concentration on malt oxidoreductases is not the same. Notably, the metal ions with appropriate concentrations of are effective to enhance total phenol content, DPPH scavenging activity, reducing power and flavor stability of the corresponding malt. The related experimental results would provide reference data for rational application of these metal ions in brewing industry.