By using surface enhanced Raman scattering, a cellulose-based SERS platform was designed to identify dangerous substances such as malachite green. On the leaf surface, silver/gold nanoparticles were synthesized. The nanoscale surface roughness of the cellulose leaf matrix should facilitate filtration, resulting in a homogeneous and well-controlled Ag/Au distribution on the leaf surface. To achieve the highest enhancement factor for Raman reporter, optimal circumstances including leaf species, concentration of silver ions and gold ions, reaction temperature, and time were investigated. Finally, the feasibility of using the proposed SERS platform to detect malachite green in fish samples was proposed.