Abstract: asic theory of electrostatic atomization is introduced, especially the atomization modes. Polyethylene glycols (PEG) are subjected to electrostatic atomization at a constant applied voltage and flow rate. The molecular weights of the PEG are varied in the range 200～400. The atomization is under the cone-jet mode by controlled the voltage and flow rate. The electrospray is deposited on silicone release paper and the sizes of the relics produced are measured. Results show that at the applied voltage and flow rate, PEG 200 could not get a stable cone-jet mode. The molecular weight had a significant effect on the mode of atomization. And for PEG 300 and PEG 400, the increase in molecular weight (viscosity increased) had the effect on increased the size of relics obtained.