The invention discloses a gold micron feather cluster modified with silver nanoparticles and a preparation method and application thereof. The gold micron feather cluster is characterized in that the silver nanoparticles are coated on an aluminum sheet, of which the surface is provided with pit arrays, wherein the particle diameter of the silver nanoparticles is 15-25 nm, and the gold micron feather cluster has the diameter of 32-658 microns and consists of gold micron feathers which consist of gold nanoparticles with the particle diameter of 200 nm to 1 micron and have the feather rod length of 16-329 microns, the feather branch length of 8-160 microns and the small feather branch length of 2-13 microns. The method comprises the following steps of: firstly obtaining the aluminum sheet, of which the surface is provided with the pit arrays which are hexagonally arranged in an orderly manner and are bowl-shaped, by using an anodic oxidation method; carrying out gold nanoparticle ion sputtering on the aluminum sheet so as to obtain the aluminum sheet coated with the gold nanoparticles; then putting the aluminum sheet coated with the gold nanoparticles in an argon atmosphere, and annealing so as to obtain the aluminum sheet coated with the gold micron feather cluster; and carrying out silver nanoparticle ion sputtering on the aluminum sheet coated with the gold micron feather cluster, thereby producing a target product. The gold micron feather cluster modified with the silver nanoparticles can serve as a surface-enhanced Raman scattering active substrate, and the content of rhodamine or tetrachlorobiphenyl attached onto the gold micron feather cluster is measured by using a laser Raman spectrometer.