This work reports a benzoic group functionalized gold nanoflower as a bridge probe for both recognition of target sialic acids and assembly of poly(N-acetylneuraminic acid) modified gold nanoparticles, which leads to plasmonic coupling of two kinds of gold nanoprobes in a single-core-multi-satellite nanostructure to produce a sensitive surface-enhanced Raman scattering (SERS) signal for the imaging of sialic acids on living cells.