To optimize the electroporation system in Dunaliella salina (D. salina), we studied the effects of growth phase of cells, electric parameters, electroporation buffer and concentration of plasmid on transformation efficiency. The results showed that a transformation efficiency of 1.81 per thousand was achieved in D. salina cells at mid-log growth phase electroporated with plasmid (DCA-bar) 10 microg/mL, voltage 0.8 kV and capacitance 25 microF. However, when glycerol was added to electroporation buffer at a final concentration of 0.4 mol/L, the transformation efficiency was increased up to 2.03 per thousand. Additionally, transformation was done with plasmids DCA-bar, NR-bar, pUomega-bar respectively, under above optimum conditions, and similar transformation efficiencies were obtained. The findings indicate that an efficient and stable system of electroporation in D. salina has been developed, providing a powerful tool for the transgenic research of D. salina.