A two-stage electrostatic precipitator (ESP) has been developed using an enhanced unipolar pre-charger with dielectric coated ground electrodes. The electrical and particle collection performance was evaluated for particles in the submicron range. By varying the voltage applied to the pre-charger, the particle charging characteristics was compared with that calculated by the theoretical model. The experimental results show that with the adoption of the pre-charger, the charging of the particles at submicron range was enhanced. Further results indicate that the collection efficiency can be improved by about 12.1%–15.9%, compared with the results obtained without the pre-charger. Higher particle collection efficiency can be achieved by increasing the voltage applied to the pre-charger. The unipolar pre-charger studied in this paper proves to be a simple and useful device to improve the submicron particle collection efficiency of conventional ESPs.