The effect of silver colloid concentration was explored for fastest delivery of silver nanoparticles into living C666 cells (a human nasopharyngeal carcinoma cell line) for intracellular surface enhanced raman scattering (SERS) by Electroporation. SERS spectra, the integrated SERS intensity and the reproducibility of spectrum were compared in 6 electroporation experiments of the same electric pulse parameters but different concentration of silver colloid. The silver nanoparticle concentration is best under the condition of 500 μl electroporation buffer containing 50 μl silver colloid using 875 V/cm, 1 ms rectangular electric pulses for electroporation twice. Increasing the concentration of silver nanoparticle could improve the SERS intensity while decrease the reproducibility of the spectrum. Moreover, the observed SERS bands of living C666 cell were tentatively assigned. This work is promising for the practical application of SERS technology, such as real time detection and analysis of the biochemical substance in living cells.