The Raman and infrared spectra of dimethylformamide (DMF)/polyacrylonitrile (PAN)/lithium perchlorate (LiClO4) have been measured and analyzed. It is found that the interaction between DMF and PAN is not strong, probably resulting from the dipole interaction between the O=C-N group of DMF and the nitrile group of PAN. Compared with the Raman spectra of DMF/LiClO4 system, it seems that the addition of PAN promotes the ion association between Li+ ions and the plasticizer molecules. However, in spite of the wide range of molar ratios of DMF/PAN/LiClO4 studied, no ion association was observed between the nitrile group of PAN and the Li+ ions in the DMF/PAN/LiClO4 system. This indicates that the details of the transport mechanism of Li+ ions in the electrolyte may be related to the plasticizer.