A method of displacement reaction between metals based on ultraviolet (UV) induction is employed to prepare a substrate of a silver/foam nickel composite structure, which is then used as the surface-enhanced Raman scattering (SERS) substrate. The simulation software COMSOL Multiphysics is utilized to calculate the electromagnetic field distributions and the theoretical enhancement factors for substrates composed of silver nanoparticles with diameters of 43 nm, 53 nm, and 63 nm,respectively. The maximum electric field intensities obtained are 43.76 V/m, 55.16 V/m, and 87.25 V/m, respectively, and the corresponding enhancement factors (EFs) are 3.67×10⁶, 9.26×10⁶, and 5.80×10⁷,^{respectively. Raman tests show that the measurement effect of the prepared substrate of the silver/foam nickel composite structure is optimal when the concentration of the reaction solution is 1.5 mol·L-1 and the displacement time is 120 min. The detection limit of the substrate on rhodamine 6G (R6G) is as low as 10-12 mol·L-1 and the EF calculated reaches 2.47×109. R6G with a concentration of 10-7 mol·L-1 is used as the probe molecule of Raman uniformity tests on the substrate of the silver/foam nickel composite structure. The relative standard deviation (RSD) values corresponding to the characteristic peaks at 613 cm-1 and 1364 cm-1 in the Raman shift spectrum are 14.5% and 13.6%, respectively, which indicates that the substrate enjoys favorable uniformity.}