Salicylic acid (SA) is effective in the treatment of coronary heart disease. In this study, a novel PEC sensor was prepared to specifically detect SA, and copper sulfide-layered double hydroxide/reduced graphene oxide (CuS-LDH/rGO) with visible light activity was chosen as the identification element and photoactive material. The photocurrent response of CuS-LDH/rGO shows linear relationship with SA concentration over a range of 1–80 μM and 160–5760 μM, with a low limit of detection (LOD) (S/N=3) of 0.35 μM. Therefore, the novel PEC-sensing strategy proposed in this study represents an ultra-sensitive method with high selectivity and stability for the detection of SA.