Electrode formed by silver nanoparticles has been obtained by a new method according to the self-assemble and electrochemical-assemble principles, which is capped by MPA and fabricated silver nanoparticles monolayer and multilayer films on pre-modified gold electrode. The performance of this modified electrode was studied by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS). The CV curve indicates that modified electrode 3(Ag-MPA)/2PDDA/4-ATP/Au was more active and steady than the others, and the EIS implies that the electrochemical impedance increased. The CV current of multilayer modified electrode was obviously higher than monolayer modified electrode in 0.5 mmol·L-1 K3 Fe(CN)6 solution.