A modified glassy carbon electrode（GCE） was prepared by electrodeposition of platimum nanoparticles（Pt NPs） and electropolymerization of 3，4-ethoxylenedioxythiophene（EDOT） onto the surface of GCE，and scanning electron microscope was employed to investigate its surface morphology.The result showed that the uniform film of poly-3，4-ethoxylenedioxythiophene（PEDOT） and aggregated Pt NPs adhered to the electrode surface.The electrochemical behaviors of chlorogenic acid（CGA） at different electrodes indicated that this modified electrode could significantly improve the electrochemical redox signal of CGA compared with the bare GCE.The experimental conditions e.g.pH value,scan rate and accumulation time were optimized.Under the optimal conditions，the oxidation peak current of CGA was linear in the concentration range of 0.2-100 μmol/L，with a detection limit of 0.05 μmol/L.The sensor was successfully used to detect CGA in real sample of Shuanghuanglian injection，with spiked recoveries of 97.7%-1021%.Furthermore，the interaction between CGA and DNA was investigated，and the binding number and the binding constant were calculated to be 3 and 1.62×103 L/mol,respectively.The result could provide not only a reference for the pharmacological research of CGA，but also a theoretical guidance for the selection of similar drugs.