Seed separation and cleaning is one of the important processes in obtaining pure high quality seed. The separation can be carried out by the properties of physical, electrical, magnetic, optical, etc. In this study, a high tension roll-type electrostatic separator was constructed to separate sunflower’s seed in order to extract pure seed and remove impurities. An extended corona discharge field was generated by three wire type electrodes in the roll-type separator. The experiment was performed in the form of factorial analysis based on a randomized complete block design with three replications. The effects of the roll rotational speed, the electrode distance from the roll and the amount of power supply as effective factors in separation were examined on sunflower and material other than grain. The pure sunflower’s seed was measured in the treatment combinations of the rotational speed (40, 50 and 60 rpm), electrode distance from roll (4, 5 and 6 cm) and the power supply voltage (20, 30 and 40 kV). Results of the compare means showed that the factors of rotational speed and electrode distance from roll had positive effect on the purity of sunflower’s seed, but the effect of power supply voltage was negative. Maximum separation occurred at in the treatment combination 60 rpm, 6 cm and 20 kV.