Abstract: The processes of a droplet icing/frosting and anti-frosting/anti-icing using a dual synthetic jet actuator (DSJA) was experimentally studied. The temperature of a semiconductor-cooled board was reduced to -30℃, and the DSJA was started before the droplet to be icing and to be frosting. The processes of the droplet icing, frosting, anti-icing and anti-frosting were observed by an electron microscope. The experimental results show that the droplet frozen gradually from bottom side to top side. What's more, the frozen rate of droplet surface was faster than inside. Because of the droplet was frozen, its density reduced and its volume increased. It was useful for a dual synthetic jet actuator to anti-frosting. Owing to the dual synthetic jet actuator, the frost on the iced droplet was not like needles but like particles. As time passed, the frost was not increasing and the height of the droplet decreased.