Brewer’s grains peptide SS-5(sequence: Ser-Pro-Asp-Arg-Ser) was synthesized by solid-phase synthesis with Fmoc protect group. Then the crude synthetic peptide was purified and desalted by HPLC, and as a result the purity was over 95%. The inhibitory activity of synthetic peptide SS-5 to α-glucosidase was detected, and the results showed that it was influenced by salt ionic concentration and the lower concentration presented higher inhibility. Furthermore, the interaction between synthetic peptide SS-5 and α-glucosidase was confirmed by circular dichroism spectrum(CD) and fluorescence quenching assays.. Therefore, a fast method of obtaining brewer’s grains peptide SS-5 with α-glucosidase inhibitory activity in quantity was proposed in this paper.