Gold nanoparticles (GN) were modified by a platelet-derived growth factor (PDGF) aptamer to obtain stable aptamer-nanogold probes (Apt-GN). The probes specifically combined with PDGF-AA to form Apt-GN–PDGF-AA clusters that exhibited a resonance Rayleigh scattering (RRS) peak at 550 nm. The RRS intensity ΔI_550nm was linear to the PDGF-AA concentration in the range of 0.33–40 ng mL⁻¹. The probes exhibit strong catalysis of the Fehling reagent–glucose Cu₂O particle reaction that can be monitored by the RRS technique at 610 nm, but the cluster is very weak. When PDGF-AA concentration increased, the Apt-GN decreased, and the RRS intensity at 610 nm decreased. The decreased RRS intensity ΔI_610nm was linear to PDGF-AA concentration in the range of 0.03–26.67 ng mL⁻¹. Accordingly, two new aptamer-nanogold RRS methods were established.