▎ 摘　　要

NOVELTY - Preparing gold-silver-graphene oxide composite material, comprises (i) preparing graphene oxide suspension with a concentration of 1-2 mg/ml, (ii) adding chitosan solution with a concentration of 6-14 mg/ml into tetrachloroauric acid solution with a concentration of 2-8 mg/ml, where the mass ratio of chitosan to tetrachloroauric acid is 1:2-1:1, and then stirring evenly, (iii) adding silver nitrate solution with a concentration of 1-2 mg/ml into the obtained solution of step (ii), where the molar ratio of tetrachloroauric acid to silver nitrate is 18:1-4:1, and then stirring evenly, (iv) adding the graphene oxide suspension into the solution obtained in step (iii), where the mass ratio of tetrachloroauric acid to graphene oxide is 1:2-1:1, and then adding ascorbic acid, where the mass ratio of ascorbic acid to graphene oxide is 5:1-2:1, and (v) stirring the solution obtained in step (iv) uniformly, centrifuging and washing to obtain final product. USE - Then composite material is useful as surface-enhanced Raman spectroscopy (SERS) substrate to enhance the Raman signal of the analyte. ADVANTAGE - The method: is simple and low cost; and produces gold-silver-graphene oxide composite material, which has excellent enhancement effect on the Raman signal of the analyte, and has enhancement factor of 6.72x 104.