A simple chemical substitution reaction method is used to grow needle-like gold nanostructures on nickel foam substrates, which are used as surface-enhanced Raman scattering (SERS) substrates to study the effect of substitution time on the properties of SERS substrates. COMSOL Multiphysics simulation software is used to simulate the electromagnetic enhancement of gold nanoparticles with the heights of 100,150,175,200 nm, respectively, and the maximum electric field intensity is 20.112, 29.060, 24.766, 21.382 V/m, respectively. The enhanced factors are 1.64×10 ⁵, 7.13×10 ⁵, 3.76×10 ⁵, and 2.09×10 ⁵, respectively. Using rhodamine 6G (R6G) solution as probe molecule, Raman characterization, detection limit test, and Raman mapping test are carried out on the nickel foam gold-plated substrate at different replacement times. The test results show that the substrate with displacement time of 10 min has the best enhancement effect, and the detection concentration of R6G molecule can reach 10 ^-8 mol·L ^-1, RSD (Relative Standard Deviation) values at the characteristic peaks of Raman shift of 613, 774, and 1364 cm ^-1 are 11.3%, 10.9%, and 11.9%, respectively. It shows that the substrate has good uniformity, the enhancement factor is 1.04×10 ⁵.