Polyacrylonitrile(PAN) is used to study the effect of the instability on electrospinning nanofibers by adding LiCl. The theoretical analysis showed that the electricity potential with high content of LiCl descends more sharply than low content of LiCl during the movement of charged fibers. The former caused jet instability to occur earlier and also caused the stability length of electrospinning jet to decrease. The experimental data agreed very well with our theoretical analysis by a series of experiments. (C) 2005 Elsevier B.V All rights reserved.