A novel DNA electrochemical as the heterobifunctional coupling agent biofilm electrode was fabricated using Sulfo-SMCC which made the sulfhydryl-modified DNAzyme, covalently immobilized on the aminated mesoporous silica nanoparticles (MSN) loaded with the electrochemical indicator methylene blue (MB) ,and then mixed with chitosan (CTS) dropping applied to the carbon paste electrodes.The preparation process of the biofilm elec- trode was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and so on.Th...