A molecularly imprinted electrochemical sensor based on gold electrode decorated with reduced graphene oxide(rGO) incorporated gold nanoparticles(AuNPs) was developed for the selective determination of lomefloxacin hydrochloride(LMX).The AuNPs-rGO nanocomposites were modified onto the gold electrode through the electrochemical reduction of graphene oxide and HAuCl4.The imprinted poly-o-phenylenediamine(o-PD) and m-dihydroxybenzene(m-DB) membrane,which was embedded in AuNPs-rGO surface,functioned as a selective recognition element for LMX.The electrochemical behaviors of the imprinted sensor were characterized by cyclic voltammetry(CV) and differential pulse voltammetry(DPV) using K3［Fe(CN)6］ as the redox probe.The results showed that the imprinted sensor displayed a high selectivity for LMX,and the introduced AuNPs-rGO composites significantly enhanced the electronic transmission and sensitivity.Under the optimal conditions,the DPV peak currents of the redox probe were linear with LMX concentrations in the range of 0.01-1.0 μmol/L,with a detection limit of 3.0 nmol/L(S/N=3).The method was applied in the determination of LMX in Xijiang water and milk samples with a satisfactory precision(RSD≤6.2%) and acceptable recoveries(88.0%-102%).