In one-pot，the thiol-functionalized SiO2 micro-spheres were prepared by a sol-gel method, and the SiO2 microspheres were modified on the surface of nickel foam by the tableting method to prepare a SiO2@NF electrochemical sensor test. The electrochemical properties of SiO2@NF were detected and optimized by differential pulse voltammetry. The results show that the prepared SiO2 microspheres are uniform in size and high in sphere formation rate, and can be firmly supported on the surface of nickel foam. Differential pulse voltammetry was used for electrochemical detection of Ag+ under optimal conditions. The linear range of the determination was 1~300 μmol/L, and the detection limit was 0.87 μmol/L. It was also used in the detection of actual water samples, better results were obtained.