A simple and sensitive electrochemical method was developed for the determination of chlorogenic acid based on Nb2O5/reduced graphene oxide(RGO) nanocomposites modified glassy carbon electrode(Nb2O5/RGO/GCE).Nb2O5/RGO composite was synthesized by a hydrothermal reduction using NbCl5 and graphene oxide(GO),and its morphology was characterized by scanning electronic microscopy(SEM).Electrochemical behaviors of chlorogenic acid on Nb2O5/RGO/GCE were studied by cyclic voltammetry(CV) and square wave voltammetric(SWV) methods.The results showed that the Nb2O5/RGO composite displayed a remarkably enhanced electrochemical activity toward the oxidation of chlorogenic acid.Conditions influencing the detection process,such as pH value of buffer solution,scan rate and accumulation time,were optimized.Under the optimized conditions, the oxidation peak current of chlorogenic acid has a good linear relationship with concentration of chlorogenic acid in the range of 5.0×10-7-1.2×10-5mol/L,with a detection limit(S/N=3) of 2.0×10-7mol/L.The proposed method was applied in the determination of chlorogenic acid in pharmaceutical products,and the spiked recoveries were in the range of 96.6%-101.5%.With good sensitivity and stability,the developed method was successfully applied in the determination of chlorogenic acid in pharmaceutical products.