In this paper,we have prepared polyacrylonitrile(PAN)/Ag nanoparticle composite nanofibers as a surface enhanced Raman scattering(SERS) substrate via an elelctrospinning technique.First,the PAN and AgNO3 were dissolved in N,N’-dimethylformamide solvent to get PAN/Ag seed solution;then the PAN/Ag seed solution was electrospun for the preparation of PAN/Ag seed composite nanofibers;Finally,the PAN/Ag seed composite nanofibers were treated by hydrazine hydrate to synthesize PAN/Ag nanoparticle composite nanofibers.The as-prepared PAN/Ag nanoparticle composite nanofibers were mixed with the probes for the SERS detection to get the SERS spectrum of the probes.The PAN/Ag nanoparticle composite nanofibers substate showed a good SERS signal when the concentration of PATP is as low as 10－6 mol·L-1.Furthermore,this kind of SERS substrate could be large-scale prepared,which showed a high commercial value.