Based on the catalytic effect of the bisphenol A aptamer-modified gold nanoparticle (Apt–GN) on the HAuCl₄-vitamin C (VC) particle reaction and its resonance Rayleigh scattering effect at 370 nm, 3.33–333.3 ng mL⁻¹ bisphenol A was detected, with a detection limit of 0.083 ng mL⁻¹.