▎ 摘　　要

NOVELTY - Preparing flexible substrate, comprises (i) taking polydimethylsiloxane as raw material, spin coating and heat curing to form flexible substrate, (ii) cutting polyimide film into a suitable size, adhering on the polydimethylsiloxane flexible substrate prepared in step (i), and printing graphene on the polyimide film by laser direct writing technology to obtain graphene flexible substrate, (iii) adding chloroauric acid solutions of different concentrations on the graphene flexible substrate obtained in step (ii), and growing gold particles in situ on the graphene by laser direct writing technology to form a large-area graphene-gold particle composite flexible substrate, and (iv) taking Raman peak of graphene as reference, ensuring quantitative detection of pesticide methyl parathion on the surface of fruits and vegetables through intensity ratio of pesticide residual Raman peak and graphene Raman peak. USE - The flexible substrate is useful: for quantitative detection of pesticide residues of methyl parathion; and in technical field of Raman detection. ADVANTAGE - The method: has simple process and convenient operation; can quickly and efficiently prepare large-area graphene gold particle composite flexible substrate.