Silver nanoparticles are prepared by redox reduction of phytic acid (IP6), trisodium citrate and silver nitrate, and IP6 terminated gold nanoparticles are synthesized by displacement reaction of silver nanoparticles with chloroauric acid. The particle size distribution and composition are studied, and it is found that the uniformity of the nanoparticles is favorable. By synthesizing surface enhanced Raman scattering (SERS) substrate, Raman probes can be accurately and efficiently detected, and the detection limit can reach 10 -8 mol·L -1. When a proper amount of Fe 3+ (mass fraction from 0.28×10 -6 to 0.56×10 -6) is added, IP6 forms a chelate with Fe 3+, which increases the number of hot spots and further enhances the SERS enhancement effect and detection sensitivity.